How to collect yeast for re-fermentation of beer. When did people start reusing yeast

At the end of fermentation, when the yeast has eaten all the sugar and its internal reserves, they settle to the bottom, as carbon dioxide it no longer stands out by them and it does not mix the mash, keeping the yeast afloat.

At the bottom of the fermentation tank, both live and obsolete yeast are in the sediment.

Live yeast can be reused for fermentation.

Can be added to yeast sediment warm water, sugar and add fresh yeast.

We do not know how much live yeast is left in the sediment, but I usually add half the usual amount to the sediment.

If you add a full dose of yeast to the mash along with the sediment, then the mash will ripen faster.

If you use sediment and full rate yeast, then you can make the hydromodule not 1:5, but 1:4.5, thereby increasing the alcohol content of the mash by a degree.

The resulting large quantity it will push the yeast, accelerate the last, slow segment of the maturation of the mash and it will be ready as if the ratio of sugar and water is 1:5.

Yeast sediment is desirable to be without flour top dressing. There is a possibility that lactic acid bacteria will start up in the sediment from top dressing and the future mash will turn sour.

The previous mash should be without top dressing or with top dressing for yeast from old jam or from old berries, citrus peels.

It is also not advisable to use the yeast sediment many times, for the same reason, the colonization of lactic acid bacteria or even putrefactive bacteria in it over time, because dead yeast is protein, food for them.

How to store the sediment of ripe mash so that it does not deteriorate, does not lose its strength.

Ideally, as soon as the mash is ripe and the yeast has settled to the bottom, the mash will clear up. We immediately prepare a new one, on the lees, with the addition of new yeast.

If we do not have time for distillation and there is no container to pour the mash for storage without sediment, then the mash must be taken out into the cold, into the frost.

At a temperature of 0 to 4 degrees, the yeast goes into hibernation, suspended animation, and stops eating.

If the storage temperature of the mash or yeast sediment will be higher, for example 5 degrees, the yeast will wake up and will require food. The higher the storage temperature, the more active yeast and the more food they need.

Yeast without food will die.

The way out is to add a little sugar to the yeast sediment stored in the refrigerator.

If the mash will not wait long in the wings for the distillation, then you can add a little sugar to it.

If the mash will stand for a long time before the distillation, then you can pour 4 liters and add 4 liters of water and 1 kilogram of sugar with a new one. Yeast will begin to feed on a new one.

If the mash is cloudy and not sweet, then the yeast is still eating its internal reserves, you can not add sugar, but it is advisable to take it out to the cold.

The container for storing yeast sediment in the refrigerator must be closed so as not to introduce foreign bacteria into it.

In order for the yeast to also multiply when stored in the refrigerator, if the temperature there is above 4 degrees, then it is desirable to saturate the yeast sediment with oxygen, it is necessary to mix it strongly.

In this case, dead yeast will be a building material, and the added sugar will be energy for the living.

At enterprises, when preparing mash or beer, the bottom of the fermentation tanks is shaped like a cone, at the end of which there is a tap. Dead yeast accumulates at the bottom of the cone and can be drained first, separating the live yeast from the dead.

At the very top of the sediment there will be fighting, breeding yeast, adapted to a high concentration of alcohol. By selecting them, you can bring out your own type of yeast.

Yeast is expensive, so it makes sense not to buy it every time, but to reuse it. Is it reasonable? and how to wash the yeast from the rest of the sediment? and should it be done at all? Let's figure it out.

How to wash yeast.

Before asking such a question, one should understand what they need to be washed from? If you read the article about that, then this question disappears. From what to wash - it becomes clear.

Here the question involuntarily arises, but how to wash the yeast?

How to wash yeast.

In different literature there are various ways yeast washing. Someone does it with plain water, others with acid, someone with alcohol, others with antibiotics ...

Let's think about what we want to get as an output? We need to get clean yeast cells, without the admixture of protein hops and other filth.

And now we just turn on the logic and begin to sort through the options for washing the yeast.

Washing yeast with water.

A yeast cell lives in beer, eats sugar, produces carbon dioxide and other metabolic products, and then you put it in water ... what happens to the cell? Water begins to draw various chemical elements out of it, because. everything strives for balance - this is a school chemistry course ... the very beginning ... And now, instead of washing the yeast, we simply kill them, because the cell is literally torn apart by osmotic pressure. And at the output we get not a pure yeast culture, but just a mess of dead cells.

Will this roam? - Maybe. If someone survives, then cells will multiply in the wort ... if they have time, of course.

And what will happen to the bacteria if they were still in the sediment? - about the same. And by introducing such “Washed Yeast” into the wort, we harm ourselves very much.

As you can see, washing the yeast with water is completely useless.

Washing yeast with acid.

This is generally a terrible horror. What will happen to you if you lie in an acid bath? well, about the same with yeast ... Oh yes! yeast is more resistant to acidic environment! - yes, but as a result we get the same thing as with water.

Can you rinse yeast with alcohol?

It would seem that yeast produces alcohol - why not?

well, if there is a very strong solution (more than 5%), then most strains will simply die. And what is the point of such a wash?

If there is a solution of less than 5%, then again, what's the point - the same water - the same osmosis, the same yeast mixture we get at the exit.

Is it worth rinsing the yeast at all?

I believe, and this is my opinion and it may not coincide with yours, or someone else's, that washing yeast is complete nonsense.

You place a living organism from a familiar environment into a new, poorer environment. There, in complete shock, he loses everything he can lose, and if after such a procedure, the yeast cell still remains alive, you place it in an enriched environment, where it begins to frantically devour everything that it can and produce maximum energy reserves. At the same time, a bunch of everything is also produced, which is then called higher alcohols and fermentation defects ...

Just imagine, you are sitting at home, warm and comfortable, and then you are out on a cold street without food and water for a month ... you eat everything that you can just survive ... and when you are finally weakened, you are placed in a grocery store where there is everything ... and all this can be taken without restrictions ... What will the body feel like? Any living organism. Yeasts are living single-celled organisms.

For this simple reason, I see no reason to wash the yeast.

How to be?

I have come to the conclusion that rinsing yeast is stupid and useless. Moreover, yeast cells can only be separated from everything else by a centrifuge, while another part of them will die. And it’s impossible to separate the living from the dead…

What if the yeast is not washed? - breed. I breed my own yeast. I bought it once and don't need it again.

Yeast washing is simple and useful procedure, which will allow you to collect yeast after fermentation, and reuse it with your own bank on next brew. Please see how to make a starter to help you better reactivate your yeast after cold storage.

SANITATION: It is necessary to disinfect everything in this process! Successful storage of yeast depends entirely on the cleanliness of the inventory.

YEAST COLLECTION: Collect the yeast that you will be rinsing and storing the same day the fermenter is empty. This yeast layer or slurry will be the basis of everything you make next. This yeast will grow new colonies in your future brews.

RECEPTION: After intensive fermentation beer at the bottom of the fermenter, a dense yeast sediment forms, and as a rule, some liquid remains with it. Gentle stirring will loosen the yeast sediment so that you can pour the yeast suspension (sometimes in chunks) into a sanitized flask or 3 liter bottle. This will require a lot of free space. Your yeast slurry will be full of suspended matter and hop particles. At first, it will probably be very cloudy and without certain layers, although we will try to fix this!

RINSING: You need to have about 2 liters (or enough) boiled and chilled (so as not to boil the yeast)water at hand. In your flask or bottle, add enough of this water to double or triple the amount of slurry currently available. Slightly mix all the contents (suspension and water) together. Cover with sanitized foil or lid.

EXPECTATION: After about 15-20 minutes of waiting, you should be able to see some noticeable separations in the slurry. Heavier suspended particles will settle fairly quickly, creating a dark layer with a lighter layer above it. On top of these dark layers, you will have a creamy liquid layer. This is what we need, water and yeast in suspension.

DIVISION: You will need several sanitized jars available to express this liquid-filled creamy yeast. Pour the creamy liquid, separating the suspended yeast from the sediment, into as many jars as needed to separate them completely. You now have 2-4 jars full of this creamy looking liquid. Seal the jars with sanitized lids and then place in the refrigerator. After a while in the fridge you will see that the liquid is now much clearer and there is a nice bright layer of pure yeast at the bottom of each jar.

STORAGE: If your sanitation practices are good, you can keep this yeast for several months. The yeast should remain closed and refrigerated in these jars until you are ready to make a yeast starter to wake it up. It would also be a good idea to mark these jars with the yeast name, date and reuse number #1 so you can keep track of how many times this yeast has been reused. Usually, after repeated applications, the yeast will begin to mutate and its characteristics may change to a large extent. You can usually be sure to reuse the yeast up to 4-5 times before you find it degraded.

REUSE: When you want to reuse this yeast strain, simply let one can of washed yeast gradually heat up to room temperature, and drain the liquid, and add the washed yeast suspension from the bottom of the jar to your new starter wort. See how to make a yeast starter.

IMPORTANT NOTES: You should always be too careful about sanitation, especially when it comes to rinsing yeast and storing it. Use a large clean glass jar (large flask or 3 liter bottle) for the steps removal and rinsing described in the procedure. Glass jars are an excellent container for the separation and storage steps described in the procedure. Be sure to sanitize the lids before closing the jars for the best preservation of the yeast. Label your jars with yeast name, date and reuse/generation number (G1, G2, ...) and so on to keep track of how many times you have washed and reused this yeast.

Norwegian researcher of the history of beer Lars Garshol in his blog dispels the myth that people did not know what yeast was until the 19th century, and talks about their possible reuse back in the Stone Age ..

Photo: Frankenmuth Brewery

You can often hear this phrase: “Before Pasteur, no one knew anything about yeast.” The opinion that yeast began to be used relatively recently did not appear yesterday. Even microbiologists adhere to this idea. So, the authors of the most important publication, who compiled the genealogical tree of yeast (Gallone et al, 2016), concluded that the two main families of brewer's yeast descended from the same ancestor around 1600 AD. e. However, there is direct evidence that mankind began to use yeast long before this time.

The earliest documents that reliably describe the brewing process date back to the 16th-17th centuries, and for their authors, brewer's yeast was by no means a novelty. They repeatedly mentioned this ingredient, they knew how to work with it, and there is nothing in these texts to indicate that the yeast was new at that time or that there is anything surprising in its use.

Take, for example, the first cookbook Denmark. It was compiled from earlier German works and published in Danish in 1616. The first recipe it gives is for baking bread, the second is a beer recipe, and it doesn't say anything about adding yeast. The authors took this fact for granted. So, the recipe says (translated from Danish):

“When adding yeast, make sure it is not too hot or too cold; their temperature should be slightly higher than the temperature of fresh milk.

There is no doubt that we are talking about yeast, since in their description the authors use the word gird, from which modern Danish is derived gær, which means "yeast". It is curious that in the original this phrase begins with the words naar du setter gird paa, and in the 20th century, Norwegian and Danish brewers used a similar expression å sette gjær på to indicate the action "add yeast".

Note: In 1616, adding yeast was such an obvious step in the brewing process that it wasn't even specifically listed in the recipe. In addition, the Danish language of that time already had a term for yeast and even a whole phrase to describe the action of adding it.

If we turn to other sources from that period, we get similar results. So, Olaf Magnus in his book of 1555 recommends using "the waste of the brewing process to obtain new beer." Christoph Kobrer in 1581 devoted an entire chapter in his opus to how to reuse yeast, whether dried or wet. Andrew Board wrote in 1542 that besides malt and water, nothing should be added to beer except yest, barme or goddesgood, which are three synonyms for the word "yeast".

In other words, adding yeast to the brewing process was as common in 16th century Europe as it is today. Therefore, whenever mankind thought to add yeast to beer, it happened long before the 16th century. But when?

Let's think logically. Sigmund Gjernes (Norwegian brewer whose yeast strain is used for production - ed.) showed me how to use the yeast preservation ring. You should soak the ring in yeast (in foam or sediment) added during the brewing process so that they settle on its surface, and then dry the ring. To reuse yeast, you need to take a small amount of wort and lower the ring into it. Ready. This is literally all that needs to be done to effectively reuse yeast. From archival documents it follows that for these purposes, in addition to wooden rings, pieces of cloth, wooden sticks and even straw rings were quite successfully used.

Thus, since the Stone Age, people have had everything they need to reuse yeast. The only thing they needed was to figure out how to transfer the resulting yeast foam or sediment from one brewing process to another. You just had to think: “What if I take the yeast foam and add it to the new wort? Will I get new foam? Just try it to make sure it works.

Do not forget that spontaneous fermentation is a rather risky undertaking that can lead to the most unexpected results. In addition, this process is far from safe. Therefore, as soon as someone astute came up with the idea of ​​​​reusing the yeast residue from a previous batch of beer, it became clear to everyone that this method was much more optimal, which is why it, apparently, soon became quite widespread.

This, however, does not give us an answer to the question of when exactly this historical moment occurred.

In Viking and prehistoric times, beer was brewed to celebrate special occasions. It was such an important and integral element of the main celebrations in a person's life that it was simply unthinkable to hold them without beer. For example, the members of the artel got together, brewed beer together, and then celebrated this or that event for several days.

Anders Christensen noted that if the spontaneous fermentation method was used, the whole process would be very risky, since nothing would guarantee that the resulting beer would be drinkable. Besides, it could take quite long time, which did not fit into the time allotted for the celebrations.

A similar situation developed on farms. Grain products used in brewing were very valuable raw materials in those days. If beer were regularly rendered unfit for consumption, it would be quite costly to produce. In the 19th century, Norwegian farmers typically brewed beer 2-3 times a year because they simply didn't have enough grain to brew it more often. During the Viking Age and even earlier, beer was brewed on almost every farm. Clearly, people have somehow managed to brew quality beer on a regular basis.

Thus, it would be logical to assume that the reuse of yeast began long before the 16th century. Can we prove it? Actually, yes.

Distillation equipment. Drawing from the manuscript of Zosimas. Source: Lars Garshol

One of the earliest "recipes", often attributed to Zosimas of Panopolitan, was not actually written by him. Zosimus lived in the 3rd and 4th centuries AD. e., long before the era of printing, so he created his works by hand in the form of manuscripts, which were then repeatedly copied. Approximately in 1000 AD. e. as part of one of these copies, a recipe for beer appeared, which was not in the original manuscript.

The recipe clearly states: "Crush the remainder and make [from the resulting mass] a cake, adding yeast to it as for bread." The text of the recipe is in Greek and uses the word ζύμη for yeast. In modern Greek it means "yeast", and from it come such terms as "zymology" (the science of fermentation) and "technology fermentation industries". It should be borne in mind, however, that we are talking about an ancient text. So can we be sure that the word in question meant "yeast" at the time the recipe was written? Here is what Max Nelson, professor and historian, says about this ancient rome, in his doctoral dissertation on beer in ancient civilizations: “In ancient Greek, the term ζύμη was used to designate yeast, and its Latin counterpart was the word fermentum”. Therefore, we are correct in our reasoning.

There are other sources that support our idea. In the 77th century A.D. e. Pliny the Elder wrote that the Iberians (Spain) and Gauls (France) used the yeast foam obtained during the fermentation of beer to bake bread, which made it lighter and tastier. It is hard to believe that these peoples, resorting to such a method, did not realize the obvious fact that it works equally effectively for brewing beer.

Max Nelson's dissertation is essentially a collection of quotes about beer taken from ancient Greek and Roman sources, presented in thematic order. So, under the heading "Yeast" the following text is given:

“In one financial document of an ancient brewer, compiled in the first century A.D. e. on a papyrus from Tebtounis, mention is made of "jugs of yeast" […], indicating the use of a fermented liquid for the fermentation of beer. On ancient Greek and ancient Egyptian papyri dating from the first and second centuries A.D. e., the profession of "yeast" (zymonrgos) is mentioned. This cumulative evidence indicates that already in the first century AD. e. there were specialists in growing and cultivating yeast for the production of bread and beer.

Model of the brewing process in ancient Egypt. Egyptian Museum of the Rosicrucians, San Jose (California).

Yeast washes are used by homebrewers to reuse strains, but in next game beer. The essence of the process - it is important to separate living cells from hop and grain residues. They settle on the bottom, which simplifies the procedure.

As a result, you can grow a viable colony to start the next fermentation. It will become the base of the starter. Yeast washing allows up to 5-6 brews after sampling. This is enough for six months ahead.

Technologically, flushing is not difficult. Prepare two in advance. glass jars, sterilize, boil water and take some foil or food film. Strictly monitor cleanliness, as this is critical to the viability of the yeast.

How to rinse yeast

Take water at room temperature. Banks are clean. The topmost edges fermentation tank walk with a disinfectant. When in doubt, where is it better to take strains - from primary or secondary fermentation. Do not hesitate, ideally from the primary. It contains much more living cells. You need to do this at the moment when you pour the wort for re-fermentation. You will see the leftover sediment, which we will use. Pour a liter of boiled cooled water.

Shake the container lightly and let the sediment settle to the bottom again. You should get a mixture with a dense layer on the bottom and liquid on top, which you pour carefully, without hitting the bottom layer, into a jar. Cover with cling film or foil and secure with a rubber band. Place in the refrigerator for half an hour to an hour. After this time, you will see how the mixture again formed a precipitate and liquid. Our task is to get the liquid, all the active strains are in it. Sediment is garbage. Carefully drain the liquid, cover again and transfer to the refrigerator for an hour.

If you see that there is a lot of sludge again, do the procedure again. This mixture can be stored for several months and used as needed. Ideally, try to control the cleanliness to prevent contamination. Can be stored in a sealed bottle.

How to add to wort

Before the day of brewing, add some wort to the mixture to make a beer yeast starter. If you don't want to use all at once, pour as much as you need for your batch, or harvest after primary fermentation. We do not recommend using the same yeast more than 4-6 times.