Hello %username%.
If you have a question right now: “Hey, what does part 2 mean - where is the first one ?!” - go urgently .
Well, for those who are already familiar with the first part, let's get straight to the point.
Yes, and I know that for many, Friday has just begun - well, that's the reason to get ready for the evening.
Come on.
At the very beginning, I will tell you about the difficult path of beer in Iceland.
Prohibition in Iceland came even earlier than in the United States - in 1915. However, the situation did not last long, because in response, tough, as they say now, counter-sanctions went: Spain, having lost the Icelandic wine market, stopped buying fish from Iceland in response. It was only possible to endure this for six years, and since 1921, wine has been excluded from the list of prohibited foods in Iceland. Beer, however, is not.
It took another 14 years for persistent Icelanders to regain the right to drink spirits: in 1935 you could drink wine, rum, whiskey and everything else, but beer could not be drunk stronger than 2,25%. At that time, the leadership of the country believed that normal beer contributed to the prosperity of depravity, because it was more accessible than strong alcohol (well, yes, of course).
The Icelanders found the solution quite simple and obvious, which even became even more attractive to me than after the European Championship in 2016: people simply diluted the allowed beer with the allowed strong alcohol. Of course, the government always meets the needs of its citizens, and that is why in 1985 the staunch teetotaler and ulcerative Minister for Human Rights (what an irony!) achieved a ban on this simple method.
Beer was finally allowed in Iceland on March 1, 1989, 74 years after the ban. And it is clear that since then March 1 in Iceland has been Beer Day: taverns are open until the morning, and locals remember how they have been waiting for the return of their favorite drink for three quarters of a century. By the way, you can also add this date to your calendar, when it is quite reasonable to skip a glass of foam.
In the next part, as an interesting story, I think I will write something about Guinness ...
But back to where we left off, namely, the ingredients of beer.
Malt.
Malt is the second most important component of beer after water. And not only beer - malt is the basis for the production of many fermented drinks - including kvass, kulagi, makhsyms, and whiskey. It is malt that is food for yeast, and therefore determines both the strength and some taste qualities. Honey, grainy, biscuit, nutty, chocolate, coffee, caramel, bready - all these flavors do not come from chemistry (fortunately or unfortunately) - but from malt. Moreover: no sane brewer will add something extra that can be obtained in this way. You'll see later that it's not just about the flavors you get from malt.
Malt is a slightly germinated cereal: barley, rye, wheat or oats. Barley malt is used always, if you drink wheat beer, then know that wheat malt in it is just an admixture with barley. Similarly, oat malt is an adjunct to barley malt and is used less frequently than wheat malt, but is used in some stouts.
There are two types of malt: base malt - it gives the wort a lot of sugar for further fermentation, but does not affect the taste too much, and special - it is poor in fermentable sugar, but it gives the beer a pronounced taste. A significant part of mass beers is produced using several base malts.
Grain raw materials intended for brewing require pre-treatment, which consists in turning it into brewing malt. The process includes the germination of grains of cereals, drying and cleaning of sprouts. Malt processing can be carried out both at the brewery and at a separate enterprise (malt plant).
The process of obtaining malt is divided into soaking and germination of seeds. During germination, chemical changes occur, new chemicals are formed. And the main role in this is played by various enzymes, which are numerous in germinating malt. We will now discuss some. Get ready, %username%, it's about to hit the brain.
So, we have ready germinated malt. Let's start mashing - this is the preparation of wort from malt. The malt is crushed, mixed with hot water, the mash (a mixture of crushed grain products) is gradually heated. A gradual increase in temperature is necessary because malt enzymes act differently at different temperatures. The temperature pauses affect the taste, strength, headiness and density of the resulting beer. And at different stages, different enzymes are turned on.
The hydrolytic breakdown of starch (amylolysis) during mashing is catalyzed by malt amylose. In addition to them, malt contains several enzymes from the groups of amyloglucosidases and transferases, which attack some of the breakdown products of starch, but in terms of quantitative ratio they are only of secondary importance during mashing.
When mashing, the natural substrate is the starch contained in the malt. Like any natural starch, it is not a single chemical substance, but a mixture containing, depending on the origin, from 20 to 25% amylose and 75-80% amylopectin.
The amylose molecule forms long, unbranched, helically folded chains consisting of α-glucose molecules mutually linked by glucosidic bonds at the α-1,4 position. The number of glucose molecules is different and ranges from 60 to 600. Amylose is soluble in water and completely hydrolyzes to maltose under the action of malt β-amylase.
The amylopectin molecule consists of short branched chains. Along with bonds in the α-1,4 position, α-1,6 bonds are also found in branched places. There are about 3000 glucose units in a molecule - amylopectin is much larger than amylose. Amylopectin is insoluble in water without heating; when heated, it forms a paste.
Malt contains two amylases. One of them catalyzes a reaction in which starch is rapidly broken down to dextrins, but relatively little maltose is formed - this amylase is called dextrinating or α-amylase (α-1,4-glucan-4-glucanohydrolase). Under the action of the second amylase, a large amount of maltose is formed - this is saccharifying amylase or β-amylase (β-1,4-glucanmaltohydrolase).
Deextrinating α-amylase is a typical component of malt. α-Amylase is activated during malting. It catalyzes the cleavage of α-1,4 glucosidic bonds of the molecules of both components of starch, i.e., amylose and amylopectin, while only the final bonds are broken unevenly inside. Thinning and dextrinization occur, manifesting itself in a rapid decrease in the viscosity of the solution (liquefaction of the mash). In natural environments, i.e. in malt extracts and mashes, α-amylase has a temperature optimum of 70°C and is inactivated at 80°C. The optimal pH zone is between 5 and 6 with a clear maximum on the pH curve. α-Amylase is very sensitive to hyperacidity (it is acid-labile): it is inactivated by oxidation at pH 3 at 0°C or at pH 4,2-4,3 at 20°C.
Saccharifying β-amylase is contained in barley and its volume increases greatly during malting (germination). β-Amylase has a high ability to catalyze the breakdown of starch to maltose. It does not dilute insoluble native starch and even starch paste. From unbranched amylase chains, β-amylase cleaves off secondary α-1,4 glucosidic bonds, namely from non-reducing (non-aldehyde) chain ends. Maltose gradually splits off from individual chains one molecule at a time. Cleavage of amylopectin also occurs, however, the enzyme attacks the branched amylopectin molecule simultaneously in several spatial chains, namely at the branching sites where the α-1,6 bonds are located, before which the cleavage stops. The temperature optimum for β-amylase in malt extracts and mashes is at 60-65°C; it is inactivated at 75°C. The optimal pH zone is 4,5-5, according to other sources - 4,65 at 40-50°C with a soft maximum on the pH curve.
Collectively, amylases are often referred to as diastase, these enzymes are found in common types of malt and in special diastatic malt, it is a natural mixture of α- and β-amylase, in which β-amylase quantitatively predominates over α-amylase. With the simultaneous action of both amylases, the hydrolysis of starch is much deeper than with the independent action of each one alone, and maltose is obtained in this case 75-80%.
The difference in the temperature optimum of α- and β-amylase is used in practice to regulate the interaction of both enzymes in that the selection of the correct temperature supports the activity of one enzyme to the detriment of the other.
In addition to the breakdown of starch, the breakdown of proteins is also extremely important. This process - proteolysis - is catalyzed during mashing by enzymes from the group of peptidases or proteases (peptide hydrolases), which hydrolyze peptide bonds -CO-NH-. They are divided into endopeptidases, or proteinases (peptidohydrolase peptide) and exopeptidases or peptidases (hydrolase dipeptide). In mashes, the substrates are the remains of the protein substance of barley, i.e. leucosin, edestin, hordein and glutelin, partially altered during malting (for example, coagulated during drying) and their cleavage products, i.e. albumoses, peptones and polypeptides.
Barley and malt contain one enzyme from the group of endopeptidases (proteinases) and at least two exopeptidases (peptidases). Their hydrolyzing action is mutually complementary. According to their properties, barley and malt proteinases are enzymes of the papain type, which are very common in plants. Their optimum temperature is between 50-60°C, the optimum pH ranges from 4,6 to 4,9 depending on the substrate. Proteinase is relatively stable at high temperatures and thus differs from peptidases. It is most stable in the isoelectric region, i.e. at pH from 4,4 to 4,6. Enzyme activity in an aqueous medium decreases already after 1 h at 30°C; at 70°C after 1 h it is completely destroyed.
Hydrolysis catalyzed by malt proteinase proceeds gradually. Several intermediate products have been isolated between proteins and polypeptides, of which the most important are fragments of peptides - peptones, also called proteoses, albumoses, etc. These are the highest cleavage products of a colloidal nature, which have typical properties of proteins. When boiled, peptones do not coagulate. Solutions have an active surface, they are viscous and easily form foam when shaken - this is extremely important in brewing!
The last degree of cleavage of proteins catalyzed by malt proteinase are polypeptides. They are only partly high-molecular substances with colloidal properties. Normally, polypeptides form molecular solutions that are easily diffusible. As a rule, they do not react like proteins and are not precipitated by tannin. Polypeptides are a substrate for peptidases that complement the action of proteinases.
The peptidase complex is represented in malt by two enzymes, but others are allowed. Peptidases catalyze the cleavage of terminal amino acid residues from peptides, with first dipeptides and finally amino acids. Peptidases are characterized by substrate specificity. Among them are dipeptidases that hydrolyze only dipeptides, and polypeptidases that hydrolyze higher peptides containing at least three amino acids in the molecule. In the group of peptidases, there are aminopolypeptidases, the activity of which determines the presence of a free amino group, and carboxypeptidases, requiring the presence of a free carboxyl group. All malt peptidases have an optimum pH in the slightly alkaline region between pH 7 and 8 and an optimum temperature of about 40°C. At pH 6, at which proteolysis occurs in germinating barley, the activity of peptidases is pronounced, while at pH 4,5–5,0 (the optimum for proteinases), peptidases are inactivated. In aqueous solutions, the activity of peptidases decreases even at 50°C; at 60°C, peptidases are quickly inactivated.
When mashing, great importance is attached to enzymes that catalyze the hydrolysis of phosphoric acid esters, as well as phospholipids of cell membranes. The cleavage of phosphoric acid is technically very important due to its direct effect on the acidity and buffering system of brewing intermediates and beer, and the fatty acids formed from phospholipids form esters during fermentation, causing various aromas. Phosphoric acid esters are the natural substrate of malt phosphoesterases, of which phytin predominates in malt. It is a mixture of calcis and magnesium salts of phytic acid, which is the hexaphosphoric ester of inositol. In phosphatides, phosphorus is bonded as an ester to glycerol, while nucleotides contain a ribose phosphorus ester bonded to a pyrimidine or purine base.
The most important malt phosphoesterase is phytase (mesoinositol hexaphosphate phosphohydrolase). She is very active. From phytin, phytase gradually splits off phosphoric acid. This produces various phosphate esters of inositol, which eventually give inositol and inorganic phosphate. Along with phytase, saccharophosphorylase, nucleotide pyrophosphatase, glycerophosphatase, and pyrophosphatase have also been described. The optimal pH of malt phosphatases is in a relatively narrow range - from 5 to 5,5. They are sensitive to high temperatures in different ways. The optimum temperature range of 40-50°C is very close to the temperature range of peptidases (proteases).
Oxygen strongly affects the process of enzyme formation - if it is lacking, the grain simply does not germinate, and light - it destroys some enzymes, in particular, diastase, and therefore malting rooms - malt houses - are arranged with little access to light.
Until the XNUMXth century, it was believed that only such malt was suitable, the germination of which did not go before the appearance of a leaf. In the XNUMXth century, it was proved that malt, in which the leaf reached a relatively large size (long malt, German Langmalz), contains significantly higher amounts of diastase, if only the malting was carried out at the lowest possible temperature.
Among other things, malt finds its use in the preparation of the so-called malt extract. Malt extract is condensed or dehydrated by evaporation wort, brewed from crushed grains of barley, rye, corn, wheat, and other cereals. The wort is gently evaporated in a vacuum at a temperature of 45 to 60°C to the consistency of a syrup, clarified, freed from astringent compounds by separation and centrifugation. In the production of beer, malt extract is rarely used, because it does not allow experimenting with a variety of tastes and colors.
And variety is very easy to get. Depending on the degree of drying, you can get different types of malt - light, dark, black. To obtain dark and especially caramel varieties, the malt is roasted. The harder the malt is roasted, the more sugars caramelize in it. The caramel flavor of the beer comes from malt with actually real caramel inside: after steaming and drying, the starch contained in the malt turns into a caramelized solid mass. It is she who will bring characteristic notes to the beer - and in the same way you can add a "burnt taste" with the help of actually burnt roasted malt. And the Germans also have “smoky beer” - rauchbier, in the preparation of which green malt smoked on fire is used: the heat and smoke from the burning fuel dry and simultaneously smoke the germinated grain. Moreover, the taste and aroma of future beer directly depend on what fuel is used for smoking malt. In the Schlenkerla brewery (which, by the way, is already over 600 years old), aged beech wood is used for these purposes, thanks to which this variety acquires a specific smoked profile - well, the attempts of these Bavarian brewers are understandable: you need to look for some original options within a narrow framework German beer purity law, however, we will talk about these and not only these “frameworks” after we discuss all the ingredients of beer.
It must also be said that it is impossible to brew beer from only dark varieties: during roasting, the enzymes necessary for saccharification of the wort are lost. and therefore any, even the darkest rauchbier will contain light malt as well.
In total, when using different varieties of malt, a whole set of different substances already enters the beer before the fermentation process, the most important of which are:
- Sugar (sucrose, glucose, maltose)
- Amino acids and peptones
- Fatty acid
- Phosphoric acid (Always Coca-Cola! Stay away from me, stay away!)
- Products of incomplete oxidation during drying of all of the above richness with a complex composition
With sugars, everything is clear - this is the future food for yeast, as well as the sweetish taste of beer (it was it that was balanced earlier with herbs, and later with hops, adding bitterness), everything is clear with products of incomplete combustion - this is a darker color, smoked and caramel taste and smell. I spoke about the importance of peptones and foam - but I will not tire of repeating it. We will return to fatty acids when we talk about yeast and the appearance of fruity aromas.
By the way, speaking about peptones, proteins and cell death, I somehow remembered one story that I read on one of the thematic publics. She's under a spoiler for some reason.
Children, women and the faint of heart do not watch!For almost 10 years, one interesting Scottish brewery, BrewDog, has produced an incredibly strong beer - as much as 55%, which for quite a long time was the strongest beer in the world. So, a very small part of the batch of this drink was packed in protein (namely protein, not protein) and other fur-bearing animals. A bottle of such a beer called The End of History (“The End of History”), in the design of which stuffed small mammals were used (they say the carcasses were simply found on the roads), cost about $750.
We will end this about malt, mentioning only that domestic malt is not even bad - and therefore is actively used along with imported.
Yeast.
Another absolutely essential component of beer is the actual yeast. Well, where without them, right?
Brewer's yeast is a fermenting microorganism. In turn, fermentation is a biochemical process based on the redox transformations of organic compounds under anaerobic conditions, that is, without oxygen. During fermentation, the substrate - and in our case, sugar - is not completely oxidized, so fermentation is energetically inefficient. With various types of fermentation, the fermentation of one molecule of glucose gives from 0,3 to 3,5 molecules of ATP (adenosine triphosphate), while aerobic (that is, with oxygen consumption) respiration with complete oxidation of the substrate has an output of 38 ATP molecules. Due to the low energy yield, fermenting microorganisms are forced to process a huge amount of the substrate. And of course, this is in our favor!
In addition to alcoholic fermentation, in which mono- and disaccharides are converted into ethanol and carbon dioxide, there is also lactic acid fermentation (the main result is lactic acid), propionic acid fermentation (the result is lactic and acetic acids), formic acid fermentation (formic acid with variants), butyric fermentation (butyric and acetic acid) and homoacetate fermentation (only acetic acid). I must say that it is unlikely that a beer lover would want something else to happen besides racially correct alcoholic fermentation - I don’t think that anyone would want to drink sour that smells like rancid butter or missing cheese. That is why the proportion of "foreign fermentation" is controlled in every possible way, in particular, by the purity of the yeast.
Yeast production is a huge industry: entire laboratories, independent or created at the brewery, are working on breeding brewer's yeast strains with certain characteristics. The recipe for yeast is often a closely guarded secret by the brewer. It is said that the peoples of northern Europe had a tradition of handing down a special brewing stick from generation to generation. Without stirring the brew with this piece of wood, beer did not work, so the stick was considered almost magical and was kept especially carefully. Of course, they did not know about yeast then and did not understand the true role of the stick, but even then they understood the value of this sacrament.
But there are exceptions to every rule. For example:
- In Belgium, lambics are brewed - this is a beer that begins to ferment on its own, thanks to microorganisms entering the wort from the air. It is believed that real lambics can only be obtained in certain regions of Belgium, and it is understandable that the fermentation there is so mixed and complex that the devil himself will break his leg. However, frankly: lambics are not for everyone, and definitely not suitable for those who believe that beer should not be sour.
- The American brewery Rogue Ales brewed an ale based on yeast, which the head brewer carefully grew in his own beard.
- His Australian colleague from the 7 Cent brewery went even further and grew wild yeast in his navel, and then released a beer based on it.
- Polish brewery The Order of Yoni brewed beer from women a few years ago. Well, as from women ... from yeast from women. The women weren't hurt at all... Well, in short, you get the idea...
During the fermentation process, brewer's yeast not only eats sugars and produces what it is supposed to, but also simultaneously perform a large number of other chemical processes. In particular, esterification processes take place - the formation of esters: what, there is alcohol, fatty acids (remember malt?) - too, you can make a lot of interesting things out of them! It can be a green apple (some American lagers have), a banana (typical of German wheat beers), a pear, or butter. Here I remember the school and various broadcasts that smelled so yum-yum-yum. But not all. Whether a drink with a fruity aroma or a delicate aroma of a mixture of fusel oil and a solvent will turn out depends on the concentration of esters, which in turn depends on various factors: fermentation temperature, must extract, yeast strain, and the amount of oxygen that has entered the must. We will talk about this when we come to consider the technology of brewing.
By the way, yeast also affects the taste - we will remember this when we talk about hops.
And now, since we have met with yeast, we can report on the only correct way to divide beer. And no, %username% is not "light" and "dark", because neither light nor dark exist, just as there are no 100% blondes and 100% brunettes. This is a division into ale and lager.
Strictly speaking, there are two types of fermentation in the eyes of brewers: top-fermentation (yeast rises to the top of the wort) - this is how ale is made, and bottom-fermentation (yeast sinks to the bottom) - this is how lager is made. It's easy to remember:
- Ale —> high fermenting yeast —> high fermentation temperature (approximately +15 to +24 °C) —> high consumption temperature (+7 to +16 °C).
- Lager —> yeast work low —> fermentation temperature low (approximately +7 to +10 °C) —> consumption temperature low (+1 to +7 °C).
Ale is the most ancient type of beer, it was brewed by the very first brewers hundreds of years ago. Now, most ales are characterized by: higher gravity, more complex taste, often fruity aroma and generally darker (compared to lagers) color. An important advantage of ales is their relatively simple and cheap production, which does not require additional refrigeration equipment, as is the case with lagers, and therefore all craft breweries can offer this or that ale.
Lager, on the other hand, appeared later: its production began to be mastered more or less tolerably only in the XNUMXth century, and only in the second half of the XNUMXth century did it begin to gain serious momentum. Modern lagers are characterized by a clearer and often more hoppy flavor and aroma, as well as a generally lighter color (although black lagers do exist) and lower ABV. The fundamental difference from ales: at the last stage of production, the lager is poured into special containers and matures there for several weeks or even months at temperatures close to zero - this process is called lagerization. Camp varieties have a longer shelf life. Due to the ease of maintaining quality stability and long shelf life, lager is the most popular type of beer in the world: almost all major breweries produce lagers. However, since production requires more sophisticated technology (remember about lagerization), as well as the presence of special frost-resistant yeast - and therefore the presence of original (namely original, not rebranded) lagers in the list of varieties offered in some craft brewery - a sign of its status and experience brewers.
Many (including myself) believe that ales are more “proper” beers than lagers. Ales are more complex in terms of aromas and flavors, and are often richer and more varied. Lagers, on the other hand, are easier to digest, often more refreshing, and on average less strong. Lager differs from ale in part because it lacks the obvious taste and aroma of yeast, which are important, and sometimes mandatory for ales.
Well, here we figured it out. Right? No, that's not true - there are variants when the beer is a hybrid of lager and ale. For example, German Kölsch is a top-fermented beer (that is, ale) that matures at low temperatures (like a lager). As a result of this hybrid production scheme, the drink has the characteristics of both types of beer: clearness, lightness and freshness side by side with subtle fruity notes on the palate and a short but pleasant sweetness. And finally, a little hop.
In general, if you, %username%, suddenly felt that you began to understand the classification of beer, then here's the last thing for you:
Let's summarize about yeast: in summary, the longer the yeast works, the more the taste and character of the beer can change. This is especially true of ales, in which the concentration of substances that affect taste and aroma is higher. For this reason, some ales are fermented in the bottle: the beer is already bottled in glass containers and is on the store shelf, but the fermentation process is still going on inside. Having bought a couple of bottles of such beer and drinking them at different times, you can feel a significant difference. At the same time, pasteurization deprives the beer of some taste characteristics, as it excludes the presence of live yeast in the drink. Actually, this is why unfiltered beer is valued by many: even after pasteurization, the remains of a yeast culture can make the drink tastier. That sediment that is visible at the bottom of the container with unfiltered beer is the remains of yeast.
But all this will be after, and now we have to list a few more optional components of beer.
More on that in the next part.
Source: www.habr.com