About beer through the eyes of a chemist. Part 1

About beer through the eyes of a chemist. Part 1




Hi% username%.

As I promised earlier, I was a little lost in connection with my business trip. No, it has not ended yet, but inspired some thoughts that I decided to share with you.

It's about beer.

I will not drown now for certain varieties, argue what taste and color in the body changes less from the moment of use to the moment ... well, you understand - I want to just talk about how I see the production process, the differences and the effects of beer on our organism in terms of chemistry.

Many people think that beer is the drink of the common people - and they are very mistaken, many consider that beer is harmful - and they are also mistaken, however, like those who believe that beer is not harmful. And we will take it apart!

Unlike the previous articles - I will try to get rid of Longrides, but rather I will divide this story into several. And if at some stage there is no interest, then I’ll just stop hurting the poor reader’s brain.

Well, let's go.

Background


The history of beer in the world goes back several millennia. The first mentions of it belong to the era of the early Neolithic. Already 6,000 years ago, people used technology to turn bread into a flavored drink - and indeed it is generally believed that beer is the oldest alcoholic drink in the world.

The history of the origin of beer began even before our era, and the laurels of the inventors belong to the Sumerians. Their cuneiform, discovered by E. Huber in Mesopotamia, contained about 15 recipes for this drink. The inhabitants of Interfluve used for making beer spelba (spelled). It was ground with barley, poured with water, herbs were added and left to ferment. On the basis of the resulting wort made a drink. Pay attention: in fact, wheat beer was invented, but no one has yet said anything about hop, that is, gruet or herbal beer was brewed. At the same time, the malt was not germinated.

The next milestone in the history of the emergence of beer was the Babylonian civilization. It was the Babylonians who figured out how to improve the drink. They germinated grain, and then dried it, getting malt. Beer on grain and malt was stored no more than a day. In order to make the drink more aromatic, spices were added to it, oak bark, tree leaves, honey - even then they invented nutritional supplements, still, before Reinhaitsgebot or, of course, the German law on the purity of beer was about 5,000 years old! < br/>
Gradually, the beer spread in ancient Egypt, Persia, India, in the Caucasus. But in ancient Greece, it was not popular because it was considered the drink of the poor. It was then that all these prejudices arose.

The history of beer was developed with the beginning of the Middle Ages. This period is called the period of the second birth of beer. It is believed that it happened in Germany. The German name Bier is derived from the old German Peor or Bror. Although the same English Ale (El) supposedly goes back to the Proto-Indo-European root, presumably with the meaning "intoxication". Indo-European origin of the root is convincingly proved in comparison with modern Danish and Norwegian øl, as well as Icelandic öl (Germanic group of languages, which also belonged to Old English) and Lithuanian and Latvian alus - beer (Baltic group of Indo-European family), North Russian ol (in the sense of intoxicating drink ), as well as Estonian õlu and Finnish olut. In short, no one knows how the words came out, because someone screwed up in ancient Babylon - well, everyone now calls beer differently. However, and cooked differently.

It was in the Middle Ages that hops were added to the drink. With its appearance, the taste of beer has improved, and its shelf life has become longer. Remember,% username%: hops was primarily a preservative for beer. Now the drink could be transported, and he became the subject of trade. Hundreds of recipes and varieties of beer.Some scientists from which regions clearly understand that the Slavs were the ancestors of the cultivation of hops, because in Russia in the 9th century brewing was widespread.

By the way, in the Middle Ages, light ales were widely used in Europe instead of water. Even children could afford beer, and yes, it was beer, and not kvass, as some people think. They drank, not because the dark ones wanted to get drunk, but because after tasting the water, it was easy to move the ends from a whole heap of already known and still unknown diseases. At the level of medicine at the level of plantain and the midwife - it was too dangerous. In addition, the so-called table beer (“small ale”) was also nutritious and went well at the dinner table in huge quantities, since there was about 1% alcohol there. The logical question is “what then killed the whole infection?” We will definitely consider.

XIX century was marked by another breakthrough in the history of beer. At first, Louis Pasteur discovered the relationship between fermentation and yeast cells. He published the results of his research in 1876, and after 5 years, in 1881, the Danish scientist Emil Christian Hansen obtained a pure culture of brewer's yeast, which was the impetus for industrial brewing.

If we talk about the history of non-alcoholic beer, then the impetus for its appearance was the Volsted Act of 1919, which marked the beginning of the era of prohibition in the United States: in fact, production, transportation and sale of alcoholic beverages were stronger than 0.5%. So it is not even a “small ale”. All the brewing companies were involved in the release of such practically non-alcoholic malt-based drinks, however, according to the law, the drink had to be called “cereal drink”, which people immediately called “rubber woman” “near-beer” (“near beer” ). In fact, in order to move from the usual, forbidden, to the new “almost-beer”, it was enough to add only one additional stage to the production process (and we will definitely remember it), which did not increase the price of the final product very quickly and allowed return to the production of the traditional drink: “I think this will be a glorious time for beer,” said US President Franklin Roosevelt, signing the act of Cullen-Harrison on March 22, 1933, which allowed the fortress to be raised to 4%. The act came into force on April 7, and therefore, since then, this date is National Day of Beer in the USA! They say that already on April 6, the Americans lined up in bars, and when the cherished midnight struck, then ... In short, the statistics say that in April 7 only one and a half million beer was drunk in the USA. Did you drink a glass of beer on April 7,%% username?



By the way, if it is interesting, in one of the following parts I will talk about an even more severe dry law - and this is not even the USSR, but Iceland.

At the moment, beer is not brewed except in Antarctica - although it is inaccurate. There are dozens of categories and hundreds of styles - and if you're interested, you can familiarize yourself with their description here . Beer is far from being as simple as it is believed that the cost of a bottle can sometimes exceed the cost of a box of wine - and I’m not talking about Chateau de la Packet.

Therefore,% username%, if you are now reading a bottle of beer while reading - be filled with respect and continue reading further.

Ingredients


Before you disassemble what beer is made of, briefly recall the production technology of this drink.

Beer - like so much in this world - is a product of incomplete combustion. In fact, fermentation is the process by which we taste this pleasure, as well as your% username, ability to read these lines is a product of incomplete burning of sugars, only in the case of beer, sugar does not burn in your brain, but in yeast metabolism chain.
As with any combustion, carbon dioxide and water are products - but remember, I said “incomplete”? And indeed: in the production of beer, yeast is not allowed to overeat (although this is not entirely correct, but it is good for a general understanding of the picture) - and therefore, in addition to carbon dioxide, alcohol is also formed.

Since the food is not pure sugar, but a mixture of various compounds - then the product is not just carbon dioxide, water and alcohol - but a whole bunch, thanks to which these very beers exist. Now I will talk about some of the main ingredients, and also incidentally debunk some myths about beer.

Water


Remembering that after all I am a chemist, I will switch to a boring chemical language.

Beer is an aqueous solution of extractives of malt that have not undergone changes during the fermentation and fermentation of beer, ethyl alcohol and flavor, which are either secondary metabolites of yeast or originating from hops. The composition of extractive substances includes non-fermented carbohydrates (α- and β-glucan), phenolic substances (anthocyanogens, oligo- and polyphenols), melanoidins, and caramels. Their content in beer, depending on the mass fraction of dry substances in the initial wort, the composition of the wort, the technological modes of fermentation and the strain characteristics of the yeast varies from 2.0 to 8.5 g/100 g of beer. The same process indicators are related to the alcohol content, the mass fraction of which in beer can be from 0.05 to 8.6%, and flavoring substances (higher alcohols, esters, aldehydes, etc.), the synthesis of which depends on the composition of the wort and especially from the fermentation regimes and the nature of the yeast. As a rule, for beer, during the fermentation of which bottom yeast is used, the concentration of the secondary products of yeast metabolism does not exceed 200 mg/l, while for beer of top fermentation, their level exceeds 300 mg/l. Bitter substances of hops constitute an even smaller share in beer, the amount of which in beer does not exceed 45 mg/l.

All this is very boring, the numbers may actually differ in larger and smaller sides, but you caught the gist of it: there is very little of this on the background of the water content in beer. Just like you,% username%, beer is about 95% water. It is not surprising that the quality of water affects beer in the most direct way. And by the way, this is one of the reasons why the same brand of beer produced by different plants in different places may differ in taste. A specific and probably the most famous example is Pilsner Urquell, which was somehow tried to be cooked in Kaluga, but nothing came of it. Now this beer is made only in the Czech Republic because of the special soft water.

No brewery will brew beer without first checking the water with which it will work - water quality is too important for the final product. The main players in this regard are the same cations and anions that you see on the bottle of any soda - only the levels are controlled not at all in the range of “50-5000 mg/l, but much more precisely.

Understand what affects the composition of the water?

Well, first of all, water must comply with SanPiN, and therefore we immediately discard heavy metals and other toxic materials - this rubbish in water should not be at all. The main restrictions for water used directly in the production of beer (for mashing) relate to such indicators as pH, hardness, the ratio between the concentrations of calcium and magnesium ions, which in drinking water is not regulated at all. Significantly less in the water for brewing should contain ions of iron, silicon, copper, nitrates, chlorides, sulfates. The presence of nitrites in water, which are strong toxins for yeast, is not allowed. Mineral components (dry residue) should be two times less in water and 2.5 times less than COD (chemical oxygen consumption - oxidability). In assessing the suitability of water for brewing, such an indicator as alkalinity was introduced, which is absent in the standards for drinking water.

In addition, additional requirements are placed on water, which is used to adjust the mass fraction of dry substances and alcohol in high-gravity brewing. This water should be, firstly, microbiologically pure, and secondly, deaerated (i.e. practically free of water-soluble oxygen) and contain even less calcium ions and bicarbonates compared to the water recommended for brewing in general.

What is high-density brewing?
If you didn’t know, then the technology of high-density brewing is to improve productivity of the brewhouse brewed wort with a mass fraction of dry substances by 4 ... 6% greater than the mass fraction of dry substances of the finished beer. Further, this wort is diluted with water to the desired mass fraction of dry substances, either prior to fermentation, or ready-made beer (yes, beer is diluted - but this is only at the plant, and I will tell about this later too). At the same time, in order to get a beer that does not differ in taste from beer produced by the classical technology, it is not recommended to increase the extract content of the initial wort by more than 15%.

It is extremely important to maintain the correct pH in water - I’m not talking at all about the taste of the finished beer, but about the process of fermentation of the wort (by the way, it was found - it doesn’t affect the taste - you just don’t feel such a subtle difference). The fact is that the pH depends on the activity of the enzymes that the yeast uses to eat. The best value is considered 5,2..5,4, but sometimes this value is shifted to a higher side in order to increase the bitterness. The pH value influences the intensity of metabolic processes in yeast cells, which is reflected in the biomass growth rate, cell growth rate and synthesis of secondary metabolites. Thus, in an acidic environment mainly ethyl alcohol is formed, while in alkaline - the synthesis of glycerol and acetic acid is intensified. Acetic acid adversely affects the process of reproduction of yeast, and therefore it must be neutralized by adjusting the pH during fermentation. For different "food" there may be a different value of the optimum pH: for example, 4.6 is needed for the metabolism of sucrose, 4.8 for maltose. pH is one of the main factors for the formation of esters, which we will talk about later and which create the very fruity smells of beer.

PH adjustment is always a balance of carbonates and bicarbonates in solution, and they determine this value. But here it is not so simple, because besides anions there are cations.

In brewing, the mineral cations that make up the water are divided into chemically active and chemically inactive. Chemically active cations are all calcium and magnesium salts: for example, the presence of calcium and magnesium (and by the way sodium with potassium), against the background of high carbonate content, raises the pH, while calcium and magnesium (here sodium and potassium are in flight) - but common with sulfates and chlorides lower the pH. Playing with the concentrations of cations and anions, it is possible to achieve the optimum value of the acidity of the medium. At the same time, brewers love calcium more than magnesium: firstly, it is the calcium ion that is associated with the flocculation of yeast, and secondly, when temporal rigidity is eliminated by boiling (like in a teapot) calcium carbonate precipitates and can be removed while the magnesium carbonate precipitates slowly and, upon cooling, the water partially dissolves again.

But in fact, calcium and magnesium are still flowers. In order not to overload the article, I’ll simply bring together some influences of impurities of ions in water on various factors of production and quality of beer.

Impact on the brewing process

  • Calcium ions - Stabilize alpha-amylase and increase its activity, resulting in increased yield of the extract. Increase the activity of proteolytic enzymes, due to this increases the content in total and α-amino nitrogen in the wort.
  • Determine the level of pH reduction of the wort during mashing, boiling the wort with hops and fermentation. Yeast flocculation is determined. The optimum concentration of ions is 45-55 mg/l wort.
  • Magnesium ions - They are part of glycolysis enzymes, i.e. necessary for both fermentation and yeast breeding.
  • Potassium ions - Stimulate the multiplication of yeast, are part of fermetnyh systems and ribosomes.
  • Iron ions - Negative effect on mashing processes. At concentrations greater than 0.2 mg/l, they can cause yeast degeneration.
  • Manganese ions - Included as a cofactor in yeast enzymes. The content should not exceed 0.2 mg/l.
  • Ammonium ions - May be present only in sewage. Absolutely unacceptable.
  • Copper ions - At concentrations of more than 10 mg/l - toxic to yeast. May be a mutagenic factor for yeast.
  • Zinc ions - At a concentration of 0.1 - 0.2 mg/l, stimulate yeast multiplication. At high concentrations inhibit the activity of α-amylase.
  • Chlorides - Reduce yeast flocculation. At a concentration of more than 500 mg/l slow down the fermentation process.
  • Hydrocarbonates - At high concentrations, they lead to an increase in pH, and therefore to a decrease in the activity of amylolytic and proteolytic enzymes, and they reduce the yield of the extract. and contribute to increasing the color of the wort. Concentration should not exceed 20 mg/l.
  • Nitrates - At concentrations of more than 10 mg/l, they are found in sinks. In the presence of bacteria of the Enterbacteriaceae family, a toxic nitrite ion is formed.
  • Silicates - Reduce fermentation activity at a concentration of more than 10 mg/l. Silicates originate mostly from malt, but sometimes, especially in spring, water can cause them to rise in beer.
  • Fluorides - Up to 10 mg/l has no effect.

Effect on the taste of beer

  • Calcium ions - Reduces tannin extraction, which gives the beer a bitter bitterness and astringent taste. Reduces the utilization of hop bitter substances.
  • Magnesium ions - Give a bitter taste to beer, which is felt at a concentration of more than 15 mg/l.
  • Sodium ions - At concentrations greater than 150 mg/l cause a salty taste. At concentrations of 75 ... 150 mg/l - reduce the fullness of taste.
  • Sulfates - Give beer astringency and bitterness, determine the aftertaste. At a concentration of more than 400 mg/l, the beer is given a “dry taste” (hi, Guiness Draft!). May precede the formation of sulfurous tastes and odors associated with the vital activity of infectious microorganisms and yeast.
  • Silicates - Affect the taste indirectly.
  • Nitrates - Negatively affect the fermentation process at a concentration of more than 25 mg/l. The possibility of the formation of toxic nitrosamines.
  • Chlorides - Give the beer a more subtle and sweet taste (yes, yes, but if there is no sodium). When the concentration of ions is about 300 mg/l, they increase the flavor of beer and give it a melon taste and aroma.
  • Iron ions - When a beer contains more than 0.5 mg/l, the color of the beer is “darkened”, and brown foam appears. Give the beer a metallic taste.
  • Manganese ions - Like the effects of iron ions, but much stronger.
  • Copper ions - Negatively affect taste stability. Softens the sour taste of beer.

Effect on colloid resistance (turbidity)

  • Calcium ions - Oxalates are precipitated, thereby reducing the possibility of oxalate turbidity in beer. Enhance protein coagulation by boiling the wort with hops. Reduce the extraction of silicon, which favorably affects the colloidal stability of beer.
  • Silicates - Reduce the colloidal stability of beer due to the formation of insoluble compounds with calcium and magnesium ions.
  • Iron ions - Accelerate oxidative processes, causing colloidal turbidity.
  • Copper ions - Negatively affect the colloidal stability of beer, acting as a catalyst for the oxidation of polyphenols.
  • Chlorides - Improve colloid resistance.

Well, what? In fact, different styles of beer were formed in different parts of the world thanks to, among other things, different water. Brewers from one locality turned out a successful beer with a pronounced malt taste and aroma, while the producers from the other came out a wonderful drink with a noticeable hop profile - all because there was different water in different regions, on the basis of which one beer was better than the other. Now, for example, the composition of water for beer is considered optimal in this form:



However, it is clear that there are always deviations - and these deviations often cause the fact that Baltika 3 from St. Petersburg is not Baltika 3 from Zaporozhye at all.

It is quite logical that any water used for beer production goes through several stages of preparation, including analysis, filtration and, if necessary, adjustment of the composition. Very often, the brewery conducts the process of water treatment: the water obtained in one way or another is subjected to chlorine removal, changes in the mineral composition and adjustment of hardness and alkalinity. All this can not bother, but then - and then, if you are lucky with the nominal composition of water - the brewery will cook only a couple of varieties. Therefore, monitoring and preparation of water is always done.

Modern technologies, if sufficient funds are available, make it possible to obtain water with almost any desired characteristics. The base can be at least urban water, although it is extracted directly from an artesian source. There are also exotic cases: one Swedish brewery, for example, brewed beer from treated sewage, and Chilean craftsmen make beer on water collected in the desert from fog. But it is clear that in the course of mass production, the expensive process of water treatment affects the final cost - and, perhaps, precisely because the already mentioned Pilsner Urquell is not produced anywhere else except at home in the Czech Republic.

I think that is enough for the first part. If my story turns out to be interesting, in the next part we will talk about two more essential ingredients of beer, and perhaps even one optional one, we will discuss why beer smells differently, whether there is “light” and “dark”, and we also touch on strange letters OG, FG, IBU, ABV, EBC. Maybe something else will, or maybe something will not, and will appear in the third part, in which I plan to walk briefly on technology, and then deal with myths and delusions regarding beer, including that it is “diluted” and "fix", also talk about whether you can drink expired beer.

Or maybe the fourth part ... The choice is yours,%% username!

Source text: About beer through the eyes of a chemist. Part 1