1st Time Yeast Harvest Just for fun

[Fastline]

I bottled a coopers real ale Kit that I had brewed using Nottingham last week

Had a go at harvesting the yeast just for fun really, i got some kilner type jars from asda cheap bolied them up and used the water to swish out the FV

Let it settle for a bit and then filled the three jars

I left them in the fridge over night, Looks like one has quiet a bit of trub and other two are nearly all yeast

I haven't tried washing the beer thats sitting on top off the yeast yet

Whats my next steps if i want to use it in another brew

[YeastWhisperer]

Your next step is to discard the jars with the most amount of trub. You are better off serial re-pitching than attempting to "bank" cropped yeast. Serial repitching will keep the culture viable. Yeast does not need to be rinsed with water. Yeast is much happier and protected when stored under beer.

[JamesF]

I shall follow this with interest. I quite fancy harvesting my own yeast for future brews rather than buying it.

James

[JamesF]

Assuming the yeast won't keep in the fridge for long, would it generally be easier to keep back a bottle of a previous brew until you want the yeast, then drink the beer and rinse the yeast into a solution of DME or similar a day or two before pitching?

James

[6470zzy]

I bottled a coopers real ale Kit that I had brewed using Nottingham last week

Just as a matter of curiosity, why did you not use the Cooper's kit yeast?

Cheers

[6470zzy]

viewtopic.php?f=72&t=42179

You might like to check out this Sticky.

[JamesF]

Interesting. I'd been led to believe that yeast didn't like being chilled for very long at all.

James

[YeastWhisperer]

Yeast rinsing, as practiced by home brewers, is not supported by science. The technique was erroneously extrapolated from research performed by the American Type Culture Collection (ATCC). Back in the nineties, the ATCC in Rockville, Maryland conducted a series of one-day courses where they taught people how to store tiny amounts of aseptically-grown yeast under sterile (i.e., autoclaved) distilled water. I attended that course. The technique involves taking well-isolated colonies from a plate and suspending them in autoclaved distilled water. The key to making the technique work is to remove all traces of nutrients from the culture, which is impossible to do with cropped yeast without a centrifuge. What happens when there are even trace amounts of nutrients is that the yeast cell's metabolism does not shut down. Instead, what occurs is rapid depletion of cellular glycogen stores, which, in turn, shortens the length of time that cells remain viable in storage.


From the following Chris White article: http://www.probrewer.com/library/archiv ... hy-longer/

Yeast is a living organism and is most happy and healthy when feeding on wort sugars. When fermentation is complete, yeast cells flocculate to the bottom of the fermenter. They then go into a resting state. Yeast under beer is fairly stable, and most brewers agree that the best place to store yeast is under beer. But two crucial factors are temperature and time.

Storing yeast under water, as opposed to under beer, is becoming more popular. Sterile distilled water storage puts yeast in a resting state, and some reports suggest yeast can be stored in this manner for years, with no refrigeration. Storage under water is generally done with small quantities of yeast, which are then propagated in a lab. But it is possible that this can be applied to storage of yeast slurries. Some brewers are now trying this. The key is to use sterile distilled water and wash the yeast slurry several times in the sterile distilled water to remove any traces of beer. This is best done with a centrifuge, but that is impractical for most craft brewers. White Labs has had mixed success with sterile water storage, so time will tell if this procedure will work for craft breweries.

A key takeaway here is that Chris acknowledged that White Labs has experienced mixed success with the technique. White Labs has a fully-equipped quality control lab at their disposal.

A Clayton Cone response to storage under water from the following page: http://www.danstaryeast.com/articles/vi ... easurement

Ad 3) It depends on how you store your yeast. There are reports that you can store yeast up to 1 year in distilled water if all sugars are removed. We have a little program running to test this and after one month the yeast is still fermenting well. But it is critical that all sugars are removed. A lot of breweries keep their yeast for up to a month under water (removing the wort/sugar residuals) without any problems.

Here's something that I posted on a different forum:

A yeast culture "owns" a batch of wort by shutting out competitors. It rapidly consumes dissolved oxygen, which shuts out aerobic microorganisms. A yeast culture also lowers the pH of the medium from around 5.2 to around 4.2, which shuts out pH sensitive anaerobic microflora. The final defense that a yeast culture mounts is the production of ethanol, which is toxic to microorganisms, including the culture itself.

Replacing green beer with boiled water strips the culture of the force field that it built for itself, which means that the water has to be completely free of wild vegetative cells (and spores that can germinate into vegetative cells) because they will feast on dead yeast cells. Bacteria cells multiply three times faster than yeast cells, which means that a small infection can overtake a larger yeast culture when pitched into fresh wort.

The best way to crop is to "top crop" at high krausen. However, top-cropping requires one to use a true top-cropping strain. Top-cropping naturally purifies a culture because wild yeast and bacteria do not floc to the top. Top-cropped yeast can be repitched almost indefinitely.

When using a non-top-cropping yeast strain, I usually leave enough liquid behind after racking to be able to swirl the solids back into suspension (my primary volume is 1/3 to 1/2 gallon larger than the volume I expect to rack). Swirling the solids back into solution using green beer, waiting a few minutes for the heaviest fraction to settle, and then decanting the liquid fraction has the same effect as rinsing with boiled water; however, it keeps the low pH, ethanol laden environment intact. If one wants to attempt to rid the culture of mutants, one can decant and discard the supernatant (liquid above the solids) as soon as a creamy layer of yeast forms on the bottom of the container.

As stated above, one of the first things that a yeast culture does when pitched into a batch of wort is to lower the pH from around 5.2 to around 4.2. One has heard that pathogens do not grow in beer. One of the reasons why pathogens do not grow in beer is due to its relatively low pH. Clostridium botulin growth is inhibited below pH 4.6.

Contrary to what was written in early amateur brewing books such as Brewing Lager Beer, brewing yeast cultures do not respire in wort due to a phenomenon known as the Crabtree effect. Hence, brewing yeasts do not go through a period of respirative (aerobic) growth before they start to reproduce fermentatively (anaerobic growth). In the presence of glucose levels above the Crabtree threshold, all reproduction is fermentative. As you probably noticed while reading Yeast, yeast cells use dissolved oxygen to build ergosterol and unsaturated fatty acid (UFA) reserves (these reserves are shared with with all of the daughter cells). Yeast cells perform this feat by shunting oxygen to the respirative (aerobic) metabolic pathway while simultaneously metabolizing the carbon source via the fermentative (anaerobic) metabolic pathway.

What this preference to reproduce fermentatively means to a brewer is that yeast cells pretty much start producing ethanol almost as soon as they are pitched into a batch of wort. While ethanol has a limiting effect on the viability of a yeast culture, it also protects the culture from infection. Boiled water is not truly sterile. Boiled tap water also tends to have a pH of at least 7.0; therefore, it raises the pH of the culture.

With the above said, most experienced amateur brewers eventually reach the conclusion that one can just crop and repitch without doing anything to separate the viable cells from the dead cells and break material, especially if they leave most of the break and hop material in the kettle. Less is definitely more when cropping yeast.

With that said, I made a starter this past weekend using yeast that I cropped two months ago (I will pitch a crop directly if it is less than 30 days old). I decanted the supernatant (the clear liquid that lies above the solids) before pitching the crop into 1L of 10% w/v (1.040) wort. The culture took off like a rocket. Within 12 hours, it had a 130mm head on top of about 38mm of wort. The only thing that I did to this crop was store to it in my brewing refrigerator.

[JamesF]

So would it be reasonable to infer from this that a simple way to harvest yeast would be to rouse the yeast into suspension in whatever is left of the beer after emptying the fermentation vessel, allow it to settle for a short while, then scoop some up of the suspended yeast into a sterile container, fit it with an airlock and keep it in the fridge until required?

I take your point about harvesting top-cropping yeast, but I'd prefer not to disturb an active fermentation for the time being. At least until I've built up a bit
of a stock of beer

James

[YeastWhisperer]

Top cropping does not hurt the beer, and nothing is going into the beer if it is outgassing CO2. Wild microflora does not crawl into one's fermentation vessel. It rides through the air on house dust. The outgassing of CO2 places the top of the fermentation vessel under positive pressure, which means that nothing riding on air currents is going to enter it. Top cropping is best performed with a true top-cropping strain. No all ale strains are true top croppers.

With that said, harvesting via swirling is best performed via careful pouring. The lip over which the thin slurry will be poured should be wiped with a cotton ball that is saturated with 70% (140 proof) ethanol or what I believe is known as surgical spirit in the UK (we call medical alcohol "isopropyl alcohol" or "rubbing alcohol"). This step is culture purity precaution that ensures the lip is clean and free of house microflora.

[slimmrock]

I gave this a go today and put it in a small Demi John to settle. If it's the middle layer I want I don't seem to have done very well...

[YeastWhisperer]

How did you take that crop? What yeast strain did you crop? The thick layer on the bottom appears to be break, but the break layer is usually darker than the yeast layer.

Separating the yeast from the break is much easier after the culture is in a smaller vessel, especially a glass vessel. Swirl the culture back into suspension. You should be able to see when the break starts to settle. Wait until most of the bottom layers settles before carefully decanting the thin slurry into another sanitized vessel after wiping the mouth of the demi-john with a surgical spirit saturated cotton ball. It takes practice to obtain a feel for the amount of time that one needs to wait for the break and dead cells to settle without waiting so long that the viable yeast settles.

[slimmrock]

It was WLP029 kolsch taking from the yeast cake after racking off the primary. I was having a bad day yesterday so ended up pouring away the water, putting the rest of smaller jars, they been in the fridge over night but haven't looked this morning. What should I do next apart from maybe tossing it all??

[YeastWhisperer]

In future, do not rinse your yeast with boiled water. It is not a biologically sound practice. It is better do nothing to the culture than rinse it with boiled water.

[barry44]

Apologies for hijacking the thread but I intend to rinse my yeast for the first time using us-05 as my guinea pig.

I reckon that I should be able to get a couple of 500ml jars full of the rinsed yeast and I will be brewing again about a fortnight to three weeks after rinsing the Yeast and storing it in the fridge.

Do you think I will be able to take it up to pitching temperature and pitch it as is or will I need a starter?

Also, I intend giving my mate on of the jars and he will be brewing within a week of rinsing, will he need a starter?

I understand that I haven't given a lot of information with regard to slurry etc but it is a step into a whole new world for me.

Can anyone can give me a walk through of the Mr malty calculator too?