{"id":34389,"date":"2019-10-31T21:58:03","date_gmt":"2019-10-31T18:58:03","guid":{"rendered":"https:\/\/prohoster.info\/blog\/o-pive-glazami-himika-chast-2\/"},"modified":"2019-10-31T21:58:03","modified_gmt":"2019-10-31T18:58:03","slug":"o-pive-glazami-himika-chast-2","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/o-pive-glazami-himika-chast-2","title":{"rendered":"O pivu o\u010dima chemika. \u010c\u00e1st 2","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p><img decoding=\"async\" alt=\"O pivu o\u010dima chemika. \u010c\u00e1st 2\" src=\"\/wp-content\/uploads\/2019\/05\/3d6d10f43fc5dcfd3dcf66e1566879ed.jpeg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nAhoj, %username%.<\/p>\n<p>Pokud m\u00e1\u0161 pr\u00e1v\u011b te\u010f ot\u00e1zku: \u201eHele, co znamen\u00e1 \u010d\u00e1st 2 \u2013 kde je ta prvn\u00ed?!\u201c \u2013 rychle jdi <noindex>tady<\/noindex>.<\/p>\n<p>Pro ty, kte\u0159\u00ed u\u017e znaj\u00ed prvn\u00ed \u010d\u00e1st, rovnou p\u0159ejdeme k v\u011bci.<\/p>\n<p>Ano, v\u00edm, \u017ee pro mnoh\u00e9 teprve za\u010dala p\u00e1tek \u2013 tak\u017ee je to p\u0159\u00edle\u017eitost p\u0159ipravit se na ve\u010der.<\/p>\n<p>Jdeme na to.<br \/>\n<noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><br \/>\nNa za\u010d\u00e1tku se p\u0159ece jen zm\u00edn\u00edm o t\u011b\u017ek\u00e9 cest\u011b piva na Islandu.<\/p>\n<p>Such\u00fd z\u00e1kon na Islandu nastal dokonce d\u0159\u00edve ne\u017e v USA \u2013 v roce 1915. Nicm\u00e9n\u011b situace dlouho nevydr\u017eela, proto\u017ee na to p\u0159i\u0161ly tvrd\u00e9, jak se dnes \u0159\u00edk\u00e1, protiopat\u0159en\u00ed: \u0160pan\u011blsko, kter\u00e9 p\u0159i\u0161lo o islandsk\u00fd trh s v\u00ednem, p\u0159estalo nakupovat islandsk\u00e9 ryby. To vydr\u017eelo jen \u0161est let, a od roku 1921 bylo v\u00edno ze seznamu zak\u00e1zan\u00fdch produkt\u016f na Islandu vy\u0159azeno. Pivo v\u0161ak ne.<\/p>\n<p>Dal\u0161\u00edch 14 let trvalo hou\u017eevnat\u00fdm Islan\u010fan\u016fm, ne\u017e si vr\u00e1tili pr\u00e1vo p\u00edt siln\u00e9 alkoholick\u00e9 n\u00e1poje: v roce 1935 bylo mo\u017en\u00e9 p\u00edt v\u00edno, rum, whisky a dal\u0161\u00ed, ale pivo sm\u011blo m\u00edt maxim\u00e1ln\u011b 2,25 %. V tehdej\u0161\u00edm veden\u00ed zem\u011b si mysleli, \u017ee norm\u00e1ln\u00ed pivo p\u0159isp\u00edv\u00e1 k rozkv\u011btu prostop\u00e1\u0161nosti, proto\u017ee je dostupn\u011bj\u0161\u00ed ne\u017e siln\u00fd alkohol (no jist\u011b, samoz\u0159ejm\u011b).<\/p>\n<p>Islan\u010fan\u00e9 na\u0161li zcela jednoduch\u00e9 a o\u010dividn\u00e9 \u0159e\u0161en\u00ed, \u010d\u00edm\u017e se mi stali je\u0161t\u011b sympati\u010dt\u011bj\u0161\u00ed, ne\u017e po mistrovstv\u00ed Evropy 2016: lid\u00e9 jednodu\u0161e \u0159edili povolen\u00e9 pivo povolen\u00fdm siln\u00fdm alkoholem. Samoz\u0159ejm\u011b, vl\u00e1da v\u017edy vych\u00e1z\u00ed vst\u0159\u00edc sv\u00fdm ob\u010dan\u016fm, a proto v roce 1985 p\u0159esv\u011bd\u010den\u00fd abstinent a \u017ealude\u010dn\u00ed pacient ministr pro lidsk\u00e1 pr\u00e1va (jak\u00e1 ironie!) dos\u00e1hl z\u00e1kazu i tohoto jednoduch\u00e9ho zp\u016fsobu.<\/p>\n<p>U\u017e\u00edv\u00e1n\u00ed piva na Islandu bylo definitivn\u011b povoleno teprve 1. b\u0159ezna 1989, tedy 74 let po jeho z\u00e1kazu. A je jasn\u00e9, \u017ee od t\u00e9 doby je 1. b\u0159ezen na Islandu Dnem piva: hospody jsou otev\u0159en\u00e9 a\u017e do r\u00e1na a m\u00edstn\u00ed vzpom\u00ednaj\u00ed, jak t\u0159i \u010dtvrt\u011b stolet\u00ed \u010dekali na n\u00e1vrat sv\u00e9ho obl\u00edben\u00e9ho n\u00e1poje. M\u016f\u017ee\u0161, mimochodem, tuto datum p\u0159idat do sv\u00e9ho kalend\u00e1\u0159e, kdy je zcela opr\u00e1vn\u011bn\u00e9 si d\u00e1t sklenici p\u011bniv\u00e9ho.<\/p>\n<p>V dal\u0161\u00ed \u010d\u00e1sti pl\u00e1nuju napsat n\u011bco zaj\u00edmav\u00e9ho o Guinnessu\u2026<\/p>\n<p>Ale vra\u0165me se k tomu, kde jsme skon\u010dili, tedy k ingredienc\u00edm piva.<\/p>\n<h4>Slad.<\/h4>\n<p>\nSlad je druhou nejd\u016fle\u017eit\u011bj\u0161\u00ed slo\u017ekou piva po vod\u011b. A nejen piva \u2014 slad tvo\u0159\u00ed z\u00e1klad pro v\u00fdrobu mnoha kva\u0161en\u00fdch n\u00e1poj\u016f, v\u010detn\u011b kv\u00e1sku, kulagy, mahsum\u016f, ale tak\u00e9 whisky. Pr\u00e1v\u011b slad slou\u017e\u00ed jako potrava pro kvasnice, a proto ur\u010duje jak s\u00edlu, tak i n\u011bkter\u00e9 chu\u0165ov\u00e9 vlastnosti. Medov\u00fd, zrnit\u00fd, biskvitov\u00fd, o\u0159echov\u00fd, \u010dokol\u00e1dov\u00fd, k\u00e1vov\u00fd, karamelov\u00fd, chlebov\u00fd \u2014 v\u0161echny tyto chut\u011b vznikaj\u00ed ne d\u00edky chemii (a\u0165 u\u017e \u0161\u0165astn\u011b nebo ne\u0161\u0165astn\u011b) \u2014 ale d\u00edky sladu. Nav\u00edc: \u017e\u00e1dn\u00fd rozumn\u00fd sl\u00e1dek nebude p\u0159id\u00e1vat nic zbyte\u010dn\u00e9ho, co lze z\u00edskat i tak. Pozd\u011bji uvid\u00ed\u0161, \u017ee nen\u00ed \u0159e\u010d pouze o chut\u00edch, kter\u00e9 lze z\u00edskat ze sladu.<\/p>\n<p>Slad je m\u00edrn\u011b kl\u00ed\u010den\u00fd obilnina: je\u010dmen, \u017eito, p\u0161enice nebo oves. Je\u010dmenn\u00fd slad se pou\u017e\u00edv\u00e1 <i>v\u017edy<\/i>, pokud pije\u0161 p\u0161eni\u010dn\u00e9 pivo, m\u00e1\u0161 na v\u011bdom\u00ed, \u017ee p\u0161eni\u010dn\u00fd slad v n\u011bm je pouze p\u0159\u00edm\u011bs je\u010dmenn\u00e9ho. Stejn\u011b tak ovsen\u00fd slad \u2014 je p\u0159\u00edm\u011bs\u00ed je\u010dmenn\u00e9ho, pou\u017e\u00edv\u00e1 se m\u00e9n\u011b \u010dasto ne\u017e p\u0161eni\u010dn\u00fd, ale nach\u00e1z\u00ed uplatn\u011bn\u00ed p\u0159i v\u00fdrob\u011b n\u011bkter\u00fdch stout\u016f.<\/p>\n<p>Slad se d\u011bl\u00ed na dva typy: z\u00e1kladn\u00ed \u2014 poskytuje mnohem v\u00edce cukr\u016f pro dal\u0161\u00ed kva\u0161en\u00ed, ale p\u0159\u00edli\u0161 neovliv\u0148uje chu\u0165, a speci\u00e1ln\u00ed \u2014 na fermentabiln\u00ed cukr je chud\u00fd, zato dod\u00e1v\u00e1 pivu v\u00fdraznou chu\u0165. V\u00fdznamn\u00e1 \u010d\u00e1st b\u011b\u017en\u00fdch druh\u016f piva se vyr\u00e1b\u00ed za pou\u017eit\u00ed n\u011bkolika z\u00e1kladn\u00edch slad\u016f.<\/p>\n<p>Obiln\u00e9 suroviny ur\u010den\u00e9 pro va\u0159en\u00ed piva vy\u017eaduj\u00ed p\u0159edchoz\u00ed zpracov\u00e1n\u00ed, kter\u00e9 spo\u010d\u00edv\u00e1 v jejich p\u0159em\u011bn\u011b na pivovarsk\u00fd slad. Proces zahrnuje kl\u00ed\u010den\u00ed zrn obilnin, su\u0161en\u00ed a \u010di\u0161t\u011bn\u00ed od kl\u00ed\u010dk\u016f. Zpracov\u00e1n\u00ed sladu m\u016f\u017ee prob\u00edhat jak v pivovaru, tak na samostatn\u00e9m podniku (sladovn\u011b).<\/p>\n<p>Proces z\u00edsk\u00e1v\u00e1n\u00ed sladu se d\u011bl\u00ed na m\u00e1\u010den\u00ed a kl\u00ed\u010den\u00ed semen. P\u0159i kl\u00ed\u010den\u00ed doch\u00e1z\u00ed k chemick\u00fdm zm\u011bn\u00e1m, tvo\u0159\u00ed se nov\u00e9 chemick\u00e9 l\u00e1tky. A hlavn\u00ed roli v tom hraj\u00ed r\u016fzn\u00e9 enzymy, kter\u00fdch je v kl\u00ed\u010d\u00edc\u00edm sladu \u2014 mnoho. N\u011bkter\u00e9 si nyn\u00ed rozebereme. P\u0159iprav se, %username%, te\u010f p\u0159ijde \u00fader na mozek.<\/p>\n<p>Tak\u017ee m\u00e1me hotov\u00fd nakl\u00ed\u010den\u00fd slad. P\u0159istupujeme k rmutov\u00e1n\u00ed \u2013 to je p\u0159\u00edprava mladiny ze sladu. Slad se drt\u00ed, sm\u00edch\u00e1 se s horkou vodou a rmut (sm\u011bs drcen\u00fdch zrnin) se postupn\u011b zah\u0159\u00edv\u00e1. Postupn\u00e9 zvy\u0161ov\u00e1n\u00ed teploty je nezbytn\u00e9, proto\u017ee p\u0159i r\u016fzn\u00fdch teplot\u00e1ch p\u016fsob\u00ed enzymy sladu r\u016fzn\u011b. Teplotn\u00ed pausy ovliv\u0148uj\u00ed chu\u0165, s\u00edlu, p\u011bnivost a hustotu v\u00fdsledn\u00e9ho piva. A p\u0159i r\u016fzn\u00fdch f\u00e1z\u00edch se aktivuj\u00ed r\u016fzn\u00e9 enzymy.<\/p>\n<p>Hydrolytick\u00e9 \u0161t\u011bpen\u00ed \u0161krobu (amilol\u00fdza) p\u0159i rmutov\u00e1n\u00ed katalyzuj\u00ed amil\u00e1zy sladu. Krom\u011b nich slad obsahuje n\u011bkolik enzym\u016f ze skupin amiloglukozid\u00e1z a transfer\u00e1z, kter\u00e9 napadaj\u00ed n\u011bkter\u00e9 produkty \u0161t\u011bpen\u00ed \u0161krobu, av\u0161ak co do kvantitativn\u00edho pom\u011bru maj\u00ed p\u0159i rmutov\u00e1n\u00ed pouze druhotn\u00fd v\u00fdznam.<\/p>\n<p>P\u0159i rmutov\u00e1n\u00ed je p\u0159\u00edrodn\u00edm substr\u00e1tem \u0161krob obsa\u017een\u00fd ve sladu. Stejn\u011b jako jak\u00fdkoli p\u0159\u00edrodn\u00ed \u0161krob, nen\u00ed jedinou chemickou l\u00e1tkou, ale sm\u011bs\u00ed, kter\u00e1 v z\u00e1vislosti na p\u016fvodu obsahuje od 20 do 25 % amil\u00f3zy a 75-80 % amilopektinu.<\/p>\n<p>Molekula amil\u00f3zy vytv\u00e1\u0159\u00ed dlouh\u00e9, nerozv\u011btven\u00e9, spir\u00e1lovit\u011b srolovan\u00e9 \u0159et\u011bzce, kter\u00e9 se skl\u00e1daj\u00ed z molekul \u03b1-gluk\u00f3zy vz\u00e1jemn\u011b propojen\u00fdch glykosidov\u00fdmi vazbami v poloze \u03b1-1,4. Po\u010det gluk\u00f3zov\u00fdch molekul je r\u016fzn\u00fd a pohybuje se od 60 do 600. Amil\u00f3za je ve vod\u011b rozpustn\u00e1 a p\u016fsoben\u00edm \u03b2-amyl\u00e1zy sladu se \u00fapln\u011b hydrolyzuje na malt\u00f3zu.<\/p>\n<p>Molekula amilopektinu se skl\u00e1d\u00e1 z kr\u00e1tk\u00fdch rozv\u011btven\u00fdch \u0159et\u011bzc\u016f. Krom\u011b vazeb v poloze \u03b1-1,4 se v rozv\u011btven\u00fdch m\u00edstech nach\u00e1zej\u00ed tak\u00e9 vazby \u03b1-1,6. Gluk\u00f3zov\u00fdch jednotek v molekule je p\u0159ibli\u017en\u011b 3000 \u2013 amilopektin je v\u00fdrazn\u011b v\u011bt\u0161\u00ed ne\u017e amil\u00f3za. Amilopektin je bez zah\u0159\u00e1t\u00ed nerozpustn\u00fd ve vod\u011b, p\u0159i zah\u0159\u00e1t\u00ed vytv\u00e1\u0159\u00ed lepidlo.<\/p>\n<p>Slad obsahuje dv\u011b amil\u00e1zy. Jedna z nich katalyzuje reakci, p\u0159i n\u00ed\u017e se rychle \u0161t\u011bp\u00ed \u0161krob na dextriny, p\u0159i\u010dem\u017e vznik\u00e1 relativn\u011b m\u00e1lo malt\u00f3zy \u2013 tato amil\u00e1za se naz\u00fdv\u00e1 dextrinizuj\u00edc\u00ed nebo \u03b1-amyl\u00e1za (\u03b1-1,4-glukan-4-glukanohydrol\u00e1za). P\u016fsoben\u00edm druh\u00e9 amil\u00e1zy vznik\u00e1 velk\u00e9 mno\u017estv\u00ed malt\u00f3zy \u2013 toto je amil\u00e1za sacharolytick\u00e1 nebo \u03b2-amyl\u00e1za (\u03b2-1,4-glukanmalt\u00f3zohydrol\u00e1za).<\/p>\n<p>Dextrinov\u00e1 \u03b1-amyl\u00e1za je typickou slo\u017ekou sladu. \u03b1-Amyl\u00e1za se aktivuje p\u0159i kl\u00ed\u010den\u00ed sladu. Katalyzuje \u0161t\u011bpen\u00ed \u03b1-1,4-glykosidov\u00fdch vazeb molekul obou slo\u017eek \u0161krobu, tedy amylozy a amylopectinu, p\u0159i\u010dem\u017e se nepravideln\u011b p\u0159eru\u0161uj\u00ed pouze kone\u010dn\u00e9 vazby. Doch\u00e1z\u00ed k z\u0159ed\u011bn\u00ed a dextrinaci, projevuj\u00edc\u00ed se rychl\u00fdm sn\u00ed\u017een\u00edm viskozity roztoku (\u0159ed\u011bn\u00ed ml\u00e1ta). V p\u0159\u00edrodn\u00edch prost\u0159ed\u00edch, tj. v sladov\u00fdch extraktech a ml\u00e1tech, m\u00e1 \u03b1-amyl\u00e1za teplotn\u00ed optimum 70 \u00b0C a inaktivuje se p\u0159i 80 \u00b0C. Optim\u00e1ln\u00ed pH z\u00f3na je od 5 do 6 s jasn\u00fdm maximem na pH k\u0159ivce. \u03b1-Amyl\u00e1za je velmi citliv\u00e1 na zv\u00fd\u0161enou kyselost (je kyselinovzdorn\u00e1): inaktivuje se oxidac\u00ed p\u0159i pH 3 p\u0159i 0 \u00b0C nebo p\u0159i pH 4,2-4,3 p\u0159i 20 \u00b0C.<\/p>\n<p>Osahariuj\u00edc\u00ed \u03b2-amyl\u00e1za se nach\u00e1z\u00ed v je\u010dmenu a jej\u00ed objem p\u0159i kl\u00ed\u010den\u00ed (kl\u00ed\u010den\u00ed) v\u00fdrazn\u011b roste. \u03b2-Amyl\u00e1za m\u00e1 vysokou schopnost katalyzovat \u0161t\u011bpen\u00ed \u0161krobu na malt\u00f3zu. Ne\u0159ed\u00ed nerozpustn\u00fd nativn\u00ed \u0161krob a dokonce ani \u0161krobovou pastu. Z nev\u011btven\u00fdch \u0159et\u011bzc\u016f a-mylozy \u03b2-amyl\u00e1za od\u0161t\u011bpuje sekund\u00e1rn\u00ed \u03b1-1,4-glykosidov\u00e9 vazby, a to od neoxidovan\u00fdch (nealdehydov\u00fdch) konc\u016f \u0159et\u011bzc\u016f. Malt\u00f3za se postupn\u011b od\u0161t\u011bpuje z jednotliv\u00fdch \u0159et\u011bzc\u016f po jedn\u00e9 molekule. \u0160t\u011bpen\u00ed amylopectinu se tak\u00e9 d\u011bje, ale enzym \u00fato\u010d\u00ed na v\u011btvenou molekulu amylopectinu sou\u010dasn\u011b na n\u011bkolika prostorov\u00fdch \u0159et\u011bzc\u00edch, a to v m\u00edstech v\u011btven\u00ed, kde se nach\u00e1zej\u00ed vazby \u03b1-1,6, p\u0159ed kter\u00fdmi \u0161t\u011bpen\u00ed p\u0159est\u00e1v\u00e1. Teplotn\u00ed optimum \u03b2-amyl\u00e1zy v sladov\u00fdch extraktech a ml\u00e1tech se nach\u00e1z\u00ed p\u0159i 60-65 \u00b0C; inaktivuje se p\u0159i 75 \u00b0C. Optim\u00e1ln\u00ed pH z\u00f3na je 4,5-5, podle jin\u00fdch \u00fadaj\u016f \u2013 4,65 p\u0159i 40-50 \u00b0C s m\u00edrn\u00fdm maximem na pH k\u0159ivce.<\/p>\n<p>Souhrnn\u011b amyl\u00e1zy \u010dasto naz\u00fdv\u00e1me diast\u00e1zou, tyto enzymy se nach\u00e1zej\u00ed ve sladu obvykl\u00fdch typ\u016f a ve speci\u00e1ln\u00edm diastatick\u00e9m sladu, co\u017e je p\u0159\u00edrodn\u00ed sm\u011bs \u03b1- a \u03b2-amyl\u00e1zy, v n\u00ed\u017e quantitativn\u011b p\u0159eva\u017euje \u03b2-amyl\u00e1za nad \u03b1-amyl\u00e1zou. P\u0159i sou\u010dasn\u00e9m p\u016fsoben\u00ed obou amyl\u00e1z je hydrol\u00fdza \u0161krobu mnohem hlub\u0161\u00ed, ne\u017e p\u0159i samostatn\u00e9m p\u016fsoben\u00ed ka\u017ed\u00e9ho z nich jednotliv\u011b, a malt\u00f3zy se p\u0159i tom z\u00edsk\u00e1v\u00e1 75-80 %.<\/p>\n<p>Rozd\u00edl teplotn\u00ed optimum \u03b1- a \u03b2-amyl\u00e1zy se v praxi vyu\u017e\u00edv\u00e1 k \u00faprav\u011b interakce obou enzym\u016f t\u00edm, \u017ee volbou spr\u00e1vn\u00e9 teploty podporuj\u00ed \u010dinnost jednoho enzymu na \u00fakor druh\u00e9ho.<\/p>\n<p>Krom\u011b \u0161t\u011bpen\u00ed \u0161krobu je tak\u00e9 nezbytn\u00e9 \u0161t\u011bpen\u00ed b\u00edlkovin. Tento proces - proteol\u00fdza - se katalyzuje p\u0159i rmutaci enzymy ze skupiny peptid\u00e1z nebo prote\u00e1z (peptidov\u00e1 hydrol\u00e1za), kter\u00e9 hydrolyzuj\u00ed peptidov\u00e9 vazby -C(O)-NH-. D\u011bl\u00ed se na endopeptid\u00e1zy, nebo prote\u00e1zov\u00e9 (peptidov\u00e9 peptidov\u00e9 hydrol\u00e1zy) a exopeptid\u00e1zy nebo peptid\u00e1zy (dipeptidov\u00e9 hydrol\u00e1zy). V rmutu jsou substr\u00e1tem zbytky proteinov\u00e9 l\u00e1tky je\u010dmene, tedy leukosinu, edestina, gordejina a glutelinu, \u010d\u00e1ste\u010dn\u011b zm\u011bn\u011bn\u00e9ho p\u0159i sladov\u00e1n\u00ed (nap\u0159\u00edklad koagulovan\u00e9ho p\u0159i su\u0161en\u00ed) a produkty jejich \u0161t\u011bpen\u00ed, tedy album\u00f3zy, peptony a polypeptidy.<\/p>\n<p>Je\u010dmen a slad obsahuj\u00ed jeden enzym ze skupiny endopeptid\u00e1z (prote\u00e1z) a alespo\u0148 dv\u011b exopeptid\u00e1zy (peptid\u00e1zy). Jejich hydrolyzuj\u00edc\u00ed \u00fa\u010dinky se vz\u00e1jemn\u011b dopl\u0148uj\u00ed. Co se t\u00fd\u010de sv\u00fdch vlastnost\u00ed, je\u010dmenn\u00e9 a sladov\u00e9 prote\u00e1zy pat\u0159\u00ed mezi enzymy typu papa\u00ednu, kter\u00e9 jsou v rostlin\u00e1ch velmi roz\u0161\u00ed\u0159en\u00e9. Jejich optim\u00e1ln\u00ed teplota se pohybuje mezi 50-60 \u00b0C, optim\u00e1ln\u00ed pH kol\u00eds\u00e1 mezi 4,6 a 4,9 v z\u00e1vislosti na substr\u00e1tu. Prote\u00e1za je relativn\u011b stabiln\u00ed p\u0159i vysok\u00fdch teplot\u00e1ch a t\u00edm se li\u0161\u00ed od peptid\u00e1z. Nejv\u00edce stabiln\u00ed je v izoelektrick\u00e9 oblasti, tedy p\u0159i pH od 4,4 do 4,6. Aktivita enzymu ve vodn\u00e9m prost\u0159ed\u00ed kles\u00e1 ji\u017e po 1 hodin\u011b p\u0159i 30 \u00b0C; p\u0159i 70 \u00b0C se po 1 hodin\u011b \u00fapln\u011b rozpad\u00e1.<\/p>\n<p>Hydrol\u00fdza, katalyzovan\u00e1 sladovou prote\u00e1zou, prob\u00edh\u00e1 postupn\u011b. Mezi b\u00edlkovinami a polypeptidy bylo identifikov\u00e1no n\u011bkolik meziprodukt\u016f, z nich\u017e nejd\u016fle\u017eit\u011bj\u0161\u00ed jsou \u00falomky peptid\u016f - peptony, naz\u00fdvan\u00e9 tak\u00e9 prote\u00f3zy, album\u00f3zy atd. To jsou nejvy\u0161\u0161\u00ed produkty \u0161t\u011bpen\u00ed kolloidn\u00ed povahy, kter\u00e9 maj\u00ed typick\u00e9 vlastnosti b\u00edlkovin. P\u0159i va\u0159en\u00ed se peptony nesr\u00e1\u017eej\u00ed. Roztoky maj\u00ed aktivn\u00ed povrch, jsou visk\u00f3zn\u00ed a p\u0159i t\u0159ep\u00e1n\u00ed snadno tvo\u0159\u00ed p\u011bnu - co\u017e je velmi d\u016fle\u017eit\u00e9 v pivovarnictv\u00ed!<\/p>\n<p>Posledn\u00ed stupe\u0148 roz\u0161t\u011bpen\u00ed b\u00edlkovin, katalyzovan\u00fdch sladov\u00fdm prote\u00e1zou, p\u0159edstavuj\u00ed polypeptidy. Ty jsou jen \u010d\u00e1ste\u010dn\u011b vysoce molekul\u00e1rn\u00edmi l\u00e1tkami s koloidn\u00edmi vlastnostmi. Norm\u00e1ln\u011b polypeptidy tvo\u0159\u00ed molekul\u00e1rn\u00ed roztoky, kter\u00e9 snadno difunduj\u00ed. Obecn\u011b nereaguj\u00ed jako b\u00edlkoviny a nejsou sr\u00e1\u017eeny t\u0159\u00edslovinou. Polypeptidy jsou substr\u00e1tem pro peptid\u00e1zy, kter\u00e9 dopl\u0148uj\u00ed \u00fa\u010dinek prote\u00e1zy.<\/p>\n<p>Kombinace peptid\u00e1z je ve sladu zastoupena dv\u011bma enzymy, av\u0161ak je povoleno i p\u0159\u00edtomnost dal\u0161\u00edch. Peptid\u00e1zy katalyzuj\u00ed od\u0161t\u011bpen\u00ed termin\u00e1ln\u00edch zbytk\u016f aminokyselin od peptid\u016f, p\u0159i\u010dem\u017e nejprve vznikaj\u00ed dipeptidy a nakonec aminokyseliny. Peptid\u00e1zy se vyzna\u010duj\u00ed substr\u00e1tovou specifi\u010dnost\u00ed. Mezi nimi jsou i dipeptid\u00e1zy, kter\u00e9 hydrolyzuj\u00ed pouze dipeptidy, a polypeptid\u00e1zy, kter\u00e9 hydrolyzuj\u00ed vy\u0161\u0161\u00ed peptidy obsahuj\u00edc\u00ed v molekule minim\u00e1ln\u011b t\u0159i aminokyseliny. Ve skupin\u011b peptid\u00e1z se rozli\u0161uj\u00ed aminopolypeptid\u00e1zy, jejich\u017e aktivita je podm\u00edn\u011bna p\u0159\u00edtomnost\u00ed voln\u00e9 aminov\u00e9 skupiny, a karboksypeptid\u00e1zy, kter\u00e9 vy\u017eaduj\u00ed p\u0159\u00edtomnost voln\u00e9 karboxylov\u00e9 skupiny. V\u0161echny sladov\u00e9 peptid\u00e1zy maj\u00ed optim\u00e1ln\u00ed pH v m\u00edrn\u011b alkalick\u00e9 oblasti mezi pH 7 a 8 a optim\u00e1ln\u00ed teplotu kolem 40 \u00b0C. P\u0159i pH 6, p\u0159i kter\u00e9m prob\u00edh\u00e1 proteol\u00fdza v kl\u00ed\u010d\u00edc\u00edm je\u010dmeni, je aktivita peptid\u00e1z v\u00fdrazn\u011b vyj\u00e1d\u0159ena, zat\u00edmco p\u0159i pH 4,5\u20135,0 (optimum prote\u00e1z) jsou peptid\u00e1zy inaktivov\u00e1ny. V aque\u00f3zn\u00edch roztoc\u00edch se aktivita peptid\u00e1z sni\u017euje ji\u017e p\u0159i 50 \u00b0C, p\u0159i 60 \u00b0C se peptid\u00e1zy rychle inaktivuj\u00ed.<\/p>\n<p>P\u0159i zkrmov\u00e1n\u00ed hraje velkou roli enzymy, kter\u00e9 katalyzuj\u00ed hydrol\u00fdzu slo\u017eit\u00fdch ester\u016f fosforov\u00e9 kyseliny a tak\u00e9 fosfolipid\u016f bun\u011b\u010dn\u00fdch membr\u00e1n. Od\u0161t\u011bpen\u00ed fosforov\u00e9 kyseliny je technicky velmi d\u016fle\u017eit\u00e9 kv\u016fli jej\u00edmu p\u0159\u00edm\u00e9mu vlivu na kyselost a pufrov\u00fd syst\u00e9m pivovarnick\u00fdch polotovar\u016f a piva, p\u0159i\u010dem\u017e mastn\u00e9 kyseliny, kter\u00e9 vznikaj\u00ed z fosfolipid\u016f, vytv\u00e1\u0159ej\u00ed slo\u017eit\u00e9 estery b\u011bhem fermentace a ovliv\u0148uj\u00ed r\u016fzn\u00e9 v\u016fn\u011b. P\u0159\u00edrodn\u00edm substr\u00e1tem sladov\u00fdch fosfoester\u00e1z jsou slo\u017eit\u00e9 estery fosforov\u00e9 kyseliny, p\u0159i\u010dem\u017e v sladu p\u0159evl\u00e1d\u00e1 fytin. Jde o sm\u011bs v\u00e1penat\u00fdch a ho\u0159e\u010dnat\u00fdch sol\u00ed fytinov\u00e9 kyseliny, kter\u00e1 je hexafosf\u00e1tov\u00fdm slo\u017een\u00fdm esterem inozitu. V fosfatidech je fosfor spojen jako slo\u017eit\u00fd ester s glycerinem, zat\u00edmco nukleotidy obsahuj\u00ed fosforylov\u00fd ester ribozy spojen\u00fd s pyrimidinovou nebo purinovou b\u00e1z\u00ed.<\/p>\n<p>Nejd\u016fle\u017eit\u011bj\u0161\u00ed sladovou fosfoester\u00e1zou je fyt\u00e1za (mezinosithexafosfatfosfoghydrol\u00e1za). Je velmi aktivn\u00ed. Fyt\u00e1za postupn\u011b od fytinu od\u0161t\u011bpuje fosforovou kyselinu. P\u0159i tom vznikaj\u00ed r\u016fzn\u00e9 fosforov\u00e9 slo\u017eit\u00e9 estery inozitu, kter\u00e9 nakonec d\u00e1vaj\u00ed inozit a anorganick\u00fd fosf\u00e1t. Spolu s fyt\u00e1zou byly pops\u00e1ny tak\u00e9 sacharofosforil\u00e1za, nukleotidpyrofosfat\u00e1za, glycerofosfat\u00e1za a pyrofosfat\u00e1za. Optim\u00e1ln\u00ed pH sladov\u00fdch fosfat\u00e1z se nach\u00e1z\u00ed v relativn\u011b \u00fazk\u00e9m rozmez\u00ed \u2014 od 5 do 5,5. Na vysok\u00e9 teploty reaguj\u00ed r\u016fzn\u011b. Optim\u00e1ln\u00ed teplotn\u00ed rozmez\u00ed 40-50 \u00b0C je velmi bl\u00edzk\u00e9 teplotn\u00edmu rozmez\u00ed peptid\u00e1z (prote\u00e1z).<\/p>\n<p>Na proces vzniku enzym\u016f m\u00e1 siln\u00fd vliv kysl\u00edk \u2014 p\u0159i jeho nedostatku zrno jednodu\u0161e nekl\u00ed\u010d\u00ed, a sv\u011btlo \u2014 ni\u010d\u00ed n\u011bkter\u00e9 enzymy, zejm\u00e9na diast\u00e1zu, a proto jsou m\u00edstnosti pro kl\u00ed\u010den\u00ed \u2014 sladovny \u2014 z\u0159izov\u00e1ny s mal\u00fdm p\u0159\u00edstupem sv\u011btla.<\/p>\n<p>A\u017e do 19. stolet\u00ed se v\u011b\u0159ilo, \u017ee je vhodn\u00fd pouze takov\u00fd slad, jeho\u017e kl\u00ed\u010den\u00ed neprob\u00edhalo p\u0159ed v\u00fdskytem l\u00edstk\u016f. V 19. stolet\u00ed bylo prok\u00e1z\u00e1no, \u017ee slad, ve kter\u00e9m l\u00edstek dos\u00e1hl relativn\u011b velk\u00e9 velikosti (dlouh\u00fd slad, n\u011bm. Langmalz), obsahuje v\u00fdrazn\u011b v\u011bt\u0161\u00ed mno\u017estv\u00ed diast\u00e1zy, pokud bylo kl\u00ed\u010den\u00ed prov\u00e1d\u011bno p\u0159i co mo\u017en\u00e1 nejni\u017e\u0161\u00ed teplot\u011b.<\/p>\n<p>Krom\u011b jin\u00e9ho se slad pou\u017e\u00edv\u00e1 i k v\u00fdrob\u011b takzvan\u00e9ho sladaov\u00e9ho extraktu. Sladaov\u00fd extrakt je zahu\u0161t\u011bn\u00fd nebo dehydratovan\u00fd vypa\u0159en\u00edm mladiny, uva\u0159en\u00e9 z drcen\u00fdch zrn je\u010dmene, \u017eita, kuku\u0159ice, p\u0161enice a dal\u0161\u00edch obilovin. Mladina je jemn\u011b odpa\u0159ena ve vakuu p\u0159i teplot\u011b od 45 do 60 \u00b0C do konzistence sirupu, potem osv\u011btlen\u00e1, zbaven\u00e1 sv\u00edrav\u00fdch l\u00e1tek metodou separace a centrifugace. V pivovarnictv\u00ed se sladaov\u00fd extrakt pou\u017e\u00edv\u00e1 pom\u011brn\u011b z\u0159\u00eddka, proto\u017ee neumo\u017e\u0148uje experimentovat s r\u016fznorodost\u00ed chuti a barvy.<\/p>\n<p>R\u016fznosti se dosahuje velmi jednodu\u0161e. V z\u00e1vislosti na stupni su\u0161en\u00ed lze z\u00edskat slad r\u016fzn\u00fdch typ\u016f \u2013 sv\u011btl\u00fd, tmav\u00fd, \u010dern\u00fd. Pro v\u00fdrobu tmav\u00fdch a zejm\u00e9na karamelov\u00fdch odr\u016fd se slad pra\u017e\u00ed. \u010c\u00edm d\u00e9le se slad pra\u017e\u00ed, t\u00edm v\u00edce cukr\u016f se v n\u011bm karamelizuje. Karamelovou chu\u0165 pivu dod\u00e1v\u00e1 slad s fakticky pravou karamelou uvnit\u0159: po zpracov\u00e1n\u00ed horkou p\u00e1rou a su\u0161en\u00ed se \u0161krob obsa\u017een\u00fd v sladu m\u011bn\u00ed na karamelizovanou tvrdou hmotu. Ta dod\u00e1 pivu charakteristick\u00e9 t\u00f3ny \u2013 a stejn\u00fdm zp\u016fsobem lze p\u0159idat \u201ep\u0159i\u010dern\u011bnou chu\u0165\u201c pomoc\u00ed fakticky sp\u00e1len\u00e9ho sladu. A N\u011bmci maj\u00ed tak\u00e9 \u201euzen\u00e9 pivo\u201c \u2013 rauchbier, p\u0159i jeho\u017e v\u00fdrob\u011b se pou\u017e\u00edv\u00e1 na ohni uzen\u00fd zelen\u00fd slad: teplo a d\u00fdm z ho\u0159\u00edc\u00edho paliva su\u0161\u00ed a sou\u010dasn\u011b ud\u00ed kl\u00ed\u010d\u00edc\u00ed zrno. Nav\u00edc chu\u0165 a aroma budouc\u00edho piva p\u0159\u00edmo z\u00e1vis\u00ed na tom, jak\u00e9 palivo se pou\u017e\u00edv\u00e1 k uzen\u00ed sladu. V pivovaru \u201eSchlenkerla\u201c (kter\u00fd mimochodem funguje u\u017e v\u00edce ne\u017e 600 let) se pro tyto \u00fa\u010dely pou\u017e\u00edv\u00e1 vyzr\u00e1l\u00e9 bukov\u00e9 d\u0159evo, d\u00edky kter\u00e9mu tato odr\u016fda z\u00edsk\u00e1v\u00e1 specifick\u00fd uzen\u00fd profil \u2013 a snahy t\u011bchto bavorsk\u00fdch pivovarn\u00edk\u016f jsou pochopiteln\u00e9: je t\u0159eba hledat n\u011bjak\u00e9 origin\u00e1ln\u00ed varianty v \u00fazk\u00fdch mez\u00edch n\u011bmeck\u00e9ho z\u00e1kona o \u010distot\u011b piva, nicm\u00e9n\u011b o t\u011bchto a dal\u0161\u00edch \u201emez\u00edch\u201c budeme hovo\u0159it po diskuzi o v\u0161ech pralesech piva.<\/p>\n<p>Je t\u0159eba tak\u00e9 \u0159\u00edci, \u017ee nen\u00ed mo\u017en\u00e9 uva\u0159it pivo pouze z tmav\u00fdch odr\u016fd: p\u0159i pra\u017een\u00ed se ztr\u00e1c\u00ed enzymy pot\u0159ebn\u00e9 pro zcarozum\u011bn\u00ed mladiny. Proto ka\u017ed\u00fd, i ten nejtemn\u011bj\u0161\u00ed rauchbier, bude obsahovat tak\u00e9 sv\u011btl\u00fd slad.<\/p>\n<p>Celkov\u011b se p\u0159i pou\u017eit\u00ed r\u016fzn\u00fdch odr\u016fd sladu do piva p\u0159ed procesem kva\u0161en\u00ed dost\u00e1v\u00e1 cel\u00e1 \u0159ada r\u016fzn\u00fdch l\u00e1tek, z nich\u017e nejd\u016fle\u017eit\u011bj\u0161\u00ed jsou:<\/p>\n<ul>\n<li>Cukry (sachar\u00f3za, gluk\u00f3za, malt\u00f3za)<\/li>\n<li>Aminokyseliny a peptony<\/li>\n<li>Nasycen\u00e9 mastn\u00e9 kyseliny<\/li>\n<li>Fosfore\u010dn\u00e1 kyselina (Always Coca-Cola! \u010cur m\u011b, \u010dur!)<\/li>\n<li>Produkty ne\u00fapln\u00e9ho oxidace p\u0159i su\u0161en\u00ed v\u0161ech v\u00fd\u0161e uveden\u00fdch l\u00e1tek s slo\u017eit\u00fdm slo\u017een\u00edm<\/li>\n<\/ul>\n<p>\nSe cukry je to jasn\u00e9 \u2014 to je budouc\u00ed potrava pro kvasnice, a tak\u00e9 sladk\u00e1 chu\u0165 piva (pr\u00e1v\u011b tu vyva\u017eovali d\u0159\u00edve bylinami, a pozd\u011bji \u2014 chmelem, p\u0159id\u00e1vaj\u00edc\u00ed ho\u0159kost), jasn\u00e9 je tak\u00e9 to, co d\u011bl\u00e1 produkty ne\u00fapln\u00e9ho spalov\u00e1n\u00ed \u2014 to je tmav\u0161\u00ed barva, uzen\u00e1 a karamelov\u00e1 chu\u0165 a v\u016fn\u011b. O d\u016fle\u017eitosti pepton\u016f a p\u011bny jsem mluvil \u2014 ale neomrz\u00edm se to opakovat. K nasycen\u00fdm mastn\u00fdm kyselin\u00e1m se je\u0161t\u011b vr\u00e1t\u00edme, a\u017e budeme mluvit o kvasnic\u00edch a vzniku ovocn\u00fdch aromat.<\/p>\n<p>Mimochodem, kdy\u017e mluv\u00edme o peptonech, b\u00edlkovin\u00e1ch a smrti bun\u011bk \u2014 vzpomenul jsem si na jeden p\u0159\u00edb\u011bh, kter\u00fd jsem \u010detl na jednom z tematick\u00fdch ve\u0159ejn\u00fdch kan\u00e1l\u016f. Je to pod spoilerem z ur\u010dit\u00e9ho d\u016fvodu.<br \/>\n<b class=\"spoiler_title\">D\u011btem, \u017een\u00e1m a slab\u0161\u00edm povah\u00e1m se nedoporu\u010duje d\u00edvat!<\/b>T\u00e9m\u011b\u0159 10 let zp\u011bt vydala jedna zaj\u00edmav\u00e1 skotsk\u00e1 pivovar BrewDog neuv\u011b\u0159iteln\u011b siln\u00e9 pivo \u2014 a\u017e 55%, kter\u00e9 bylo dlouhou dobu nejsiln\u011bj\u0161\u00edm pivem na sv\u011bt\u011b. Velmi mal\u00e1 \u010d\u00e1st \u0161ar\u017ee tohoto n\u00e1poje byla zabalen\u00e1 v b\u00edlkovin\u011b (p\u0159esn\u011b b\u00edlkovin\u011b, ne b\u00edlku) a jin\u00fdch hu\u0148at\u00fdch zv\u00ed\u0159atech. Lahev tohoto piva s n\u00e1zvem The End of History (\u201eKonec historie\u201c), jej\u00ed\u017e design zahrnoval prepar\u00e1ty drobn\u00fdch savc\u016f (\u0159\u00edk\u00e1 se, \u017ee t\u011bla byla jednodu\u0161e nalezena na silnic\u00edch), st\u00e1la kolem 750 dolar\u016f.<br \/>\n<img decoding=\"async\" alt=\"O pivu o\u010dima chemika. \u010c\u00e1st 2\" src=\"\/wp-content\/uploads\/2019\/05\/3e4081f88edb0bc6c24445596b79b58c.jpeg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nNa tomto m\u00edst\u011b s sladov\u00e1n\u00edm kon\u010d\u00edme, zm\u00edn\u00edme pouze, \u017ee dom\u00e1c\u00ed slad nen\u00ed v\u016fbec \u0161patn\u00fd \u2014 a proto se aktivn\u011b pou\u017e\u00edv\u00e1 vedle importovan\u00fdch.<\/p>\n<h4>Kvasnice.<\/h4>\n<p>\nDal\u0161\u00ed naprosto nezbytnou slo\u017ekou piva jsou vlastn\u011b kvasnice. A kde bychom bez nich byli, \u017ee?<\/p>\n<p>Pivovarsk\u00e9 kvasnice jsou mikroorganismy, kter\u00e9 prov\u00e1d\u011bj\u00ed fermentaci. Samotn\u00e1 fermentace (angl. fermentation) je biochemick\u00fd proces zalo\u017een\u00fd na oxida\u010dn\u011b-reduk\u010dn\u00edch p\u0159em\u011bn\u00e1ch organick\u00fdch slou\u010denin za anaerobn\u00edch podm\u00ednek, tedy bez p\u0159\u00edstupu kysl\u00edku. P\u0159i fermentaci se substr\u00e1t \u2013 v na\u0161em p\u0159\u00edpad\u011b cukr \u2013 oxiduje pouze \u010d\u00e1ste\u010dn\u011b, tak\u017ee je fermentace energeticky m\u00e1lo efektivn\u00ed. P\u0159i r\u016fzn\u00fdch typech fermentace p\u0159em\u011bna jedn\u00e9 molekuly gluk\u00f3zy poskytuje od 0,3 do 3,5 molekul ATP (adenosintrifosf\u00e1tu), p\u0159i\u010dem\u017e aerobn\u00ed (tedy s vyu\u017eit\u00edm kysl\u00edku) d\u00fdch\u00e1n\u00ed s \u00faplnou oxidac\u00ed substr\u00e1tu m\u00e1 v\u00fdt\u011b\u017enost 38 molekul ATP. Vzhledem k n\u00edzk\u00e9mu energetick\u00e9mu v\u00fdt\u011b\u017eku jsou fermenta\u010dn\u00ed mikroorganismy nuceny zpracov\u00e1vat obrovsk\u00e9 mno\u017estv\u00ed substr\u00e1tu. A to n\u00e1m samoz\u0159ejm\u011b vyhovuje!<\/p>\n<p>Krom\u011b alkoholick\u00e9 fermentace, p\u0159i kter\u00e9 se mono- a disacharidy p\u0159em\u011b\u0148uj\u00ed na ethanol a oxid uhli\u010dit\u00fd, existuje tak\u00e9 kyselina ml\u00e9\u010dn\u00e1 (kone\u010dn\u00fd v\u00fdsledek \u2013 kyselina ml\u00e9\u010dn\u00e1), propionov\u00e1 fermentace (v\u00fdsledkem jsou kyselina ml\u00e9\u010dn\u00e1 a octov\u00e1), mraven\u010d\u00ed fermentace (mraven\u010d\u00ed kyselina s variantami), m\u00e1seln\u00e1 fermentace (m\u00e1seln\u00e1 a octov\u00e1 kyselina) a homoacet\u00e1tov\u00e1 fermentace (pouze octov\u00e1 kyselina). Je t\u0159eba \u0159\u00edci, \u017ee sotva by p\u0159\u00edznivec piva cht\u011bl, aby krom\u011b rasov\u011b spr\u00e1vn\u00e9 alkoholick\u00e9 fermentace doch\u00e1zelo k n\u011b\u010demu jin\u00e9mu \u2013 mysl\u00edm, \u017ee by si nikdo nep\u0159\u00e1l p\u00edt kysel\u00e9 pivo, kter\u00e9 von\u00ed jako zka\u017een\u00fd olej nebo zka\u017een\u00fd s\u00fdr. Proto je pod\u00edl \"ciz\u00ed fermentace\" p\u0159\u00edsn\u011b kontrolov\u00e1n, zejm\u00e9na \u010distotou kvasnic. <\/p>\n<p>V\u00fdroba kvasnic je obrovsk\u00fd pr\u016fmysl: na \u0161lecht\u011bn\u00ed kmen\u016f pivovarsk\u00fdch kvasnic s r\u016fzn\u00fdmi vlastnostmi pracuj\u00ed cel\u00e9 laborato\u0159e \u2013 nez\u00e1visl\u00e9 nebo zalo\u017een\u00e9 p\u0159i pivovarech. Receptura kvasnic \u010dasto p\u0159edstavuje tajemstv\u00ed, kter\u00e9 pivovarn\u00edk d\u016fkladn\u011b chr\u00e1n\u00ed. \u0158\u00edk\u00e1 se, \u017ee u n\u00e1rod\u016f severn\u00ed Evropy existovala tradice p\u0159ed\u00e1vat z generace na generaci speci\u00e1ln\u00ed pivovarskou h\u016fl. Bez m\u00edch\u00e1n\u00ed piva touto d\u0159ev\u011bnou h\u016flkou se pivo nezdarilo, a tak byla h\u016fl pova\u017eov\u00e1na za cosi jako kouzelnou a uchov\u00e1vala se obzvl\u00e1\u0161\u0165 pe\u010dliv\u011b. Samoz\u0159ejm\u011b, \u017ee o kvasnic\u00edch se tehdy nev\u011bd\u011blo a skute\u010dn\u00e1 \u00faloha h\u016flky se nech\u00e1pala, ale u\u017e tehdy ch\u00e1pali hodnotu tohoto tajemstv\u00ed.<\/p>\n<p>Ale na ka\u017ed\u00e9 pravidlo existuj\u00ed v\u00fdjimky. Nap\u0159\u00edklad:<\/p>\n<ul>\n<li>V Belgii se va\u0159\u00ed lambiky \u2014 to je pivo, kter\u00e9 fermentuje samo, d\u00edky mikroorganism\u016fm, kter\u00e9 se dost\u00e1vaj\u00ed do mladiny ze vzduchu. Pova\u017euje se, \u017ee prav\u00e9 lambiky lze z\u00edskat pouze v ur\u010dit\u00fdch oblastech Belgie, a je jasn\u00e9, \u017ee fermentace tam je tak sm\u00ed\u0161en\u00e1 a slo\u017eit\u00e1, \u017ee by se v tom s\u00e1m \u010f\u00e1bel ztratil. Nicm\u00e9n\u011b, abych byl up\u0159\u00edmn\u00fd: lambiky jsou pro labu\u017en\u00edky a rozhodn\u011b se nehod\u00ed t\u011bm, kdo si mysl\u00ed, \u017ee pivo by nem\u011blo kysnout.<\/li>\n<li>Americk\u00fd pivovar Rogue Ales uva\u0159il ale na z\u00e1klad\u011b kvasnic, kter\u00e9 hlavn\u00ed sl\u00e1dek pe\u010dliv\u011b p\u011bstoval ve sv\u00e9m vousu.<\/li>\n<li>Jeho australsk\u00fd kolega z pivovaru 7 Cent \u0161el je\u0161t\u011b d\u00e1l a vyp\u011bstoval divok\u00e9 kvasnice u sebe v pupku a pak vypustil pivo na jejich b\u00e1zi.<\/li>\n<li>Polsk\u00fd pivovar The Order of Yoni p\u0159ed n\u011bkolika lety uva\u0159il pivo z \u017een. No, jak z \u017een\u2026 z kvasnic z \u017een. \u017deny nezaznamenaly v\u016fbec \u017e\u00e1dnou \u00fajmu\u2026 No, prost\u011b v\u00ed\u0161, jak to mysl\u00edm\u2026<\/li>\n<\/ul>\n<p>\nPivn\u00ed kvasnice b\u011bhem fermentace nejen konzumuj\u00ed cukry a produkuj\u00ed to, co maj\u00ed, ale z\u00e1rove\u0148 vykon\u00e1vaj\u00ed velk\u00e9 mno\u017estv\u00ed dal\u0161\u00edch chemick\u00fdch proces\u016f. Konkr\u00e9tn\u011b prob\u00edhaj\u00ed procesy esterifikace \u2014 tvorby slo\u017eit\u00fdch ester\u016f: co, alkohol je, mastn\u00e9 kyseliny (pamatuje\u0161 na slad?) \u2014 tak\u00e9, z nich lze ud\u011blat spoustu zaj\u00edmav\u00e9ho! To m\u016f\u017ee b\u00fdt jak zelen\u00e9 jablko (m\u00e1 to n\u011bkter\u00e9 americk\u00e9 le\u017e\u00e1ky), tak ban\u00e1n (typick\u00e9 pro n\u011bmeck\u00e9 p\u0161eni\u010dn\u00e9 pivo), hru\u0161ka a m\u00e1slo. Tady mi p\u0159ipom\u00edn\u00e1 \u0161kola a r\u016fzn\u00e9 estery, kter\u00e9 von\u011bly tak, \u017ee to bylo m\u0148am-m\u0148am-m\u0148am. Ale ne v\u0161echny. Zda n\u00e1poj dostane ovocnou v\u016fni nebo jemnou v\u016fni sm\u011bsi p\u00e1lenky a rozpou\u0161t\u011bdla \u2014 z\u00e1vis\u00ed na koncentraci slo\u017eit\u00fdch ester\u016f, co\u017e zase z\u00e1vis\u00ed na r\u016fzn\u00fdch faktorech: teplot\u011b fermentace, extraktivnosti mladiny, druhu kvasnic a mno\u017estv\u00ed kysl\u00edku, kter\u00e9 se dostalo do mladiny. O tom si promluv\u00edme, a\u017e se dostaneme k technologii va\u0159en\u00ed piva. <\/p>\n<p>Chu\u0165ov\u011b maj\u00ed kvasnice tak\u00e9 vliv \u2014 o tom si vzpomeneme, a\u017e budeme mluvit o chmelu.<\/p>\n<p>A te\u010f, kdy\u017e u\u017e jsme se sezn\u00e1mili s kvasnicemi, m\u016f\u017eeme \u0159\u00edct o jedin\u00e9m spr\u00e1vn\u00e9m zp\u016fsobu d\u011blen\u00ed piva. A ne, %username%, to nen\u00ed \u201esv\u011btl\u00e9\u201c a \u201etmav\u00e9\u201c, proto\u017ee ani sv\u011btl\u00e9, ani tmav\u00e9 neexistuje, stejn\u011b jako neexistuj\u00ed 100% blond\u00fdnky a 100% brunetky. To je \u2014 d\u011blen\u00ed na ale a le\u017e\u00e1k.<\/p>\n<p>P\u0159esn\u011b \u0159e\u010deno, kva\u0161en\u00ed u sl\u00e1dk\u016f prob\u00edh\u00e1 ve dvou typech: svrchn\u00ed (kvasnice se zdvihaj\u00ed na povrch mladiny) \u2013 tak vznik\u00e1 ale, a spodn\u00ed (kvasnice klesaj\u00ed na dno) \u2013 tak se vyr\u00e1b\u00ed lager. Snadno si to zapamatujete:<\/p>\n<ul>\n<li>Ale \u2013&gt; kvasnice kvas\u00ed vysoko \u2013&gt; teplota kva\u0161en\u00ed je vysok\u00e1 (p\u0159ibli\u017en\u011b od +15 do +24 \u00b0C) \u2013&gt; teplota p\u0159i pod\u00e1v\u00e1n\u00ed je vysok\u00e1 (od +7 do +16 \u00b0C).<\/li>\n<li>Lager \u2013&gt; kvasnice pracuj\u00ed n\u00edzko \u2013&gt; teplota kva\u0161en\u00ed je n\u00edzk\u00e1 (p\u0159ibli\u017en\u011b od +7 do +10 \u00b0C) \u2013&gt; teplota p\u0159i pod\u00e1v\u00e1n\u00ed je n\u00edzk\u00e1 (od +1 do +7 \u00b0C).<\/li>\n<\/ul>\n<p>\nAle je nejstar\u0161\u00ed typ piva, p\u0159esn\u011b to va\u0159ili prvn\u00ed sl\u00e1dci p\u0159ed stovkami let. Dnes je pro v\u011bt\u0161inu ale\u016f charakteristick\u00e1: vy\u0161\u0161\u00ed hustota, slo\u017eit\u011bj\u0161\u00ed chu\u0165, \u010dasto ovocn\u00e1 aroma a v\u011bt\u0161inou tmav\u0161\u00ed (ve srovn\u00e1n\u00ed s lagery) barva. D\u016fle\u017eitou v\u00fdhodou ale\u016f je relativn\u011b jednoduch\u00e1 a levn\u00e1 v\u00fdroba, kter\u00e1 nevy\u017eaduje dodate\u010dn\u00e9 chladic\u00ed za\u0159\u00edzen\u00ed, jak je tomu u lager\u016f, a proto mohou v\u0161echny mal\u00e9 pivovary nab\u00edzet n\u011bjak\u00fd ale.<\/p>\n<p>Lager se objevil pozd\u011bji: p\u0159im\u011b\u0159en\u011b kvalitn\u00ed v\u00fdrobu za\u010dali osvojovat teprve v 15. stolet\u00ed, a teprve ve druh\u00e9 polovin\u011b 19. stolet\u00ed za\u010dala nab\u00edrat na kvalit\u011b. Modern\u00ed lagery se vyzna\u010duj\u00ed jasn\u011bj\u0161\u00ed a \u010dasto chmelovit\u011bj\u0161\u00ed chut\u00ed a aroma, a tak\u00e9, jak je obvykle, sv\u011btlou barvou (i kdy\u017e existuj\u00ed i \u010dern\u00e9 lagery) a ni\u017e\u0161\u00edm obsahem alkoholu. Z\u00e1sadn\u00edm rozd\u00edlem od ale\u016f je, \u017ee v z\u00e1v\u011bre\u010dn\u00e9 f\u00e1zi v\u00fdroby se lager p\u0159el\u00e9v\u00e1 do speci\u00e1ln\u00edch n\u00e1dob a tam zraje n\u011bkolik t\u00fddn\u016f nebo dokonce m\u011bs\u00edc\u016f p\u0159i t\u00e9m\u011b\u0159 nulov\u00fdch teplot\u00e1ch \u2013 tento proces se naz\u00fdv\u00e1 lagerizace. Lagerov\u00e9 odr\u016fdy maj\u00ed del\u0161\u00ed trvanlivost. D\u00edky snadn\u00e9 \u00fadr\u017eb\u011b stabiln\u00ed kvality a dlouh\u00e9 \u017eivotnosti je lager nejpopul\u00e1rn\u011bj\u0161\u00ed typ piva na sv\u011bt\u011b: prakticky v\u0161echny velk\u00e9 pivovary vyr\u00e1b\u011bj\u00ed lagery. Nicm\u00e9n\u011b, proto\u017ee v\u00fdroba vy\u017eaduje slo\u017eit\u011bj\u0161\u00ed technologii (nezapome\u0148me na lagerizaci), stejn\u011b jako speci\u00e1ln\u00ed odoln\u00e9 kvasnice \u2013 proto p\u0159\u00edtomnost origin\u00e1ln\u00edch (skute\u010dn\u011b origin\u00e1ln\u00edch, a ne p\u0159ebrandovan\u00fdch) lager\u016f v nab\u00eddce n\u011bjak\u00e9ho mal\u00e9ho pivovaru je znakem jeho statusu a zku\u0161enosti sl\u00e1dk\u016f.<\/p>\n<p>Mnoz\u00ed (v\u010detn\u011b m\u011b) se domn\u00edvaj\u00ed, \u017ee ale je \u201espr\u00e1vn\u011bj\u0161\u00ed\u201c pivo ve srovn\u00e1n\u00ed s le\u017e\u00e1ky. Ale jsou komplexn\u011bj\u0161\u00ed z hlediska v\u016fn\u00ed a chut\u00ed, \u010dasto jsou hutn\u011bj\u0161\u00ed a rozmanit\u011bj\u0161\u00ed. Na druhou stranu jsou le\u017e\u00e1ky sn\u00e1ze srozumiteln\u00e9, \u010dasto osv\u011b\u017euj\u00edc\u00ed a pr\u016fm\u011brn\u011b m\u00e9n\u011b siln\u00e9. Le\u017e\u00e1k se od ale li\u0161\u00ed tak\u00e9 t\u00edm, \u017ee neobsahuje v\u00fdraznou chu\u0165 a v\u016fni kvasnic, kter\u00e9 jsou pro ale d\u016fle\u017eit\u00e9 a n\u011bkdy i nezbytn\u00e9.<\/p>\n<p>Tak a m\u00e1me jasno. M\u00e1me pravdu? Ne, nen\u00ed to pravda \u2014 existuj\u00ed varianty, kdy pivo je hybridem le\u017e\u00e1ku a ale. Nap\u0159\u00edklad n\u011bmeck\u00e9 K\u00f6lsch je pivo s vrchn\u00edm kva\u0161en\u00edm (tedy ale), kter\u00e9 zraje p\u0159i n\u00edzk\u00fdch teplot\u00e1ch (jako le\u017e\u00e1k). V d\u016fsledku takov\u00e9ho hybridn\u00edho v\u00fdrobn\u00edho sch\u00e9matu m\u00e1 n\u00e1poj charakteristiky obou typ\u016f piva: srozumitelnost, lehkost a sv\u011b\u017eest se m\u00eds\u00ed s nepatrn\u00fdmi ovocn\u00fdmi t\u00f3ny v chuti a kr\u00e1tkou, ale p\u0159\u00edjemnou sladkost\u00ed. A jako posledn\u00ed kapka trocha chmele.<\/p>\n<p>Pokud jsi, %username%, najednou poc\u00edtil, \u017ee rozum\u00ed\u0161 klasifikaci piva, tady m\u00e1\u0161 na z\u00e1v\u011br:<br \/>\n<img decoding=\"async\" alt=\"O pivu o\u010dima chemika. \u010c\u00e1st 2\" src=\"\/wp-content\/uploads\/2019\/05\/8064a64e8ce4db61e18ce690a6847f76.jpeg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nShrneme to ohledn\u011b kvasnic: \u010c\u00edm d\u00e9le kvasnice pracuj\u00ed, t\u00edm v\u00edce se m\u016f\u017ee zm\u011bnit chu\u0165 a charakter piva. To se obzvl\u00e1\u0161\u0165 t\u00fdk\u00e1 ale, kde je vy\u0161\u0161\u00ed koncentrace l\u00e1tek ovliv\u0148uj\u00edc\u00edch chu\u0165 a v\u016fni. Z tohoto d\u016fvodu n\u011bkter\u00e9 odr\u016fdy ale p\u0159edpokl\u00e1daj\u00ed dokva\u0161ov\u00e1n\u00ed v l\u00e1hvi: pivo je u\u017e nalito do sklen\u011bn\u00e9 n\u00e1doby a stoj\u00ed na polici obchodu, ale uvnit\u0159 st\u00e1le prob\u00edh\u00e1 proces kva\u0161en\u00ed. Koup\u00ed n\u011bkolik lahv\u00ed takov\u00e9ho piva a jejich po\u017eit\u00edm v r\u016fznou dobu m\u016f\u017ee\u0161 poc\u00edtit zna\u010dn\u00fd rozd\u00edl. Z\u00e1rove\u0148 pasterizace zbavuje pivo n\u011bkter\u00fdch chu\u0165ov\u00fdch zvl\u00e1\u0161tnost\u00ed, proto\u017ee vylu\u010duje p\u0159\u00edtomnost \u017eiv\u00fdch kvasnic. Pr\u00e1v\u011b proto je mnoh\u00fdmi cen\u011bno nefiltruj\u00edc\u00ed pivo: i po pasterizaci zbytky kvasinkov\u00e9 kultury mohou ud\u011blat n\u00e1poj chutn\u011bj\u0161\u00ed. Ten sediment, kter\u00fd je vid\u011bt na dn\u011b n\u00e1doby s nefiltruj\u00edc\u00edm pivem \u2014 to jsou zbytky kvasnic.<\/p>\n<p>Ale to v\u0161echno bude pozd\u011bji, nyn\u00ed mus\u00edme vyjmenovat je\u0161t\u011b n\u011bkolik nepovinn\u00fdch slo\u017eek piva.<\/p>\n<p>O tom \u2014 u\u017e v dal\u0161\u00ed \u010d\u00e1sti.<br \/>\n<br \/>Zdroj: habr.com<\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u041f\u0440\u0438\u0432\u0435\u0442, %username%. \u0415\u0441\u043b\u0438 \u0443 \u0442\u0435\u0431\u044f \u043f\u0440\u044f\u043c\u043e \u0441\u0435\u0439\u0447\u0430\u0441 \u0432\u043e\u0437\u043d\u0438\u043a \u0432\u043e\u043f\u0440\u043e\u0441: \u00ab\u042d\u0439, \u0447\u0442\u043e \u0437\u043d\u0430\u0447\u0438\u0442 \u0447\u0430\u0441\u0442\u044c 2 \u2014 \u0430 \u0433\u0434\u0435 \u043f\u0435\u0440\u0432\u0430\u044f?!\u00bb \u2014 \u0441\u0440\u043e\u0447\u043d\u043e \u0438\u0434\u0442\u0438 \u0441\u044e\u0434\u0430. \u041d\u0443 \u0430 \u0434\u043b\u044f \u0442\u0435\u0445, \u043a\u0442\u043e \u0443\u0436\u0435 \u0437\u043d\u0430\u043a\u043e\u043c \u0441 \u043f\u0435\u0440\u0432\u043e\u0439 \u0447\u0430\u0441\u0442\u044c\u044e \u2014 \u043f\u0435\u0440\u0435\u0445\u043e\u0434\u0438\u043c \u043d\u0435\u043f\u043e\u0441\u0440\u0435\u0434\u0441\u0442\u0432\u0435\u043d\u043d\u043e \u043a \u0434\u0435\u043b\u0443. \u0414\u0430, \u0438 \u044f \u0437\u043d\u0430\u044e, \u0447\u0442\u043e \u0434\u043b\u044f \u043c\u043d\u043e\u0433\u0438\u0445 \u043f\u044f\u0442\u043d\u0438\u0446\u0430 \u0442\u043e\u043b\u044c\u043a\u043e \u043d\u0430\u0447\u0430\u043b\u0430\u0441\u044c \u2014 \u043d\u0443 \u0432\u043e\u0442 \u0438 \u043f\u043e\u0432\u043e\u0434 \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u0438\u0442\u044c\u0441\u044f \u043a \u0432\u0435\u0447\u0435\u0440\u0443. [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":25912,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-34389","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.3 - aioseo.com -->\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<meta name=\"author\" content=\"Yuri Gagarin\"\/>\n\t<link rel=\"canonical\" href=\"https:\/\/prohoster.info\/cs\/blog\/news\/o-pive-glazami-himika-chast-2\" \/>\n\t\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 5.0.3\" \/>\n\t\t<meta property=\"og:locale\" content=\"cs_CZ\" \/>\n\t\t<meta property=\"og:site_name\" content=\"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 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