How to Save Yeast from Fermenter
Of course, you’re working on how to save yeast from a fermenter. It’s just silly to let all that perfectly good yeast go to waste!
Furthermore, the process is simple and almost as quick as just dumping.
So you might as well!
Brewers and Yeast
For literally thousands of years, brewers have been forming a relationship with their yeast.
What began as a happy accident and a “miracle” grew into a love affair that has lasted to this day.
Anthropologists tell us that beer was likely discovered as a result of a woman out collecting her grain harvest and leaving it out in the rain in what was likely a sudden storm.
While she ran for cover, the grain got soaked, got soggy, and began fermenting.
When she returned several days later, she would have found the equivalent of a very light beer and some rising bread dough.
Not one to waste scarce resources, she would have served the fresh rainwater to her family, only to find the euphoric effect of this nutrient rich and toxin free drink.
It was not long before every family drank ale with their meals as the alcohol in the drink would clean out any contaminants from river or creek water, offering a safe and healthy beverage to consume.
This early ale would have been very low in alcohol, around 1 or 2%, as the starches in the grain do not offer much sugar for the yeast to ferment, but it was only a matter of time before brewers took hold of this delight and learned to malt or roast their grain and then crack it.
This process converts the starches to sugars and then exposes those sugars to the water in which the grain is boiled and steeped.
Now we have real ale.
Brewers noticed early on as well the clumping formations on the surface of their brew once the krausening was completed, and they learned that those flocculated clumps were the secret ingredient to their beloved beer.
From there, brewers learned to crop, harvest, and store their yeast for pitching into their next batches, which made the brewing process much more predictable and easier to control.
Cropping yeast also makes for a more consistent batch, and if there is one thing customers demand is consistency.
A Return to Old Ways
With the rise of industrialization and all of the benefits it brought us, from women being welcomed into the workforce to the expansion of the middle class, it also separated us from many of our ancient traditions.
When Louis Pasteur was able to pinpoint exactly what yeast was and how it fermented beer, corporations grabbed hold of the opportunity to package and sell yeast to brewers, and out of convenience, many brewers lost their knowledge of harvesting their own yeast.
But it never lasts long, our forgetfulness; it usually just takes a crisis or two.
Now, with so many smaller craft brewers coming to the market, interest has risen in experimenting with wild, native yeasts, with other aromas and flavors, and as a result, more brewers are discovering the wonders of yeast and how it operates.
Add to that an inflation and unpredictable supply and demand chains, and more and more brewers are returning to those old ways.
After all, why not?
How to Save Yeast from Fermenter
As discussed above, it’s easy!
There are two ways to save yeast from the fermenter; you can do it either after primary fermentation or after secondary.
Either way, you will end up with a thriving yeast population eager to get to work on the next batch.
While many brewers have suspected for some time that fermentation kills yeast, the contrary is actually true.
The fermentation process is one way in which yeast reproduce, so at the end of either primary or secondary fermentation, you will have plenty of fresh, vital, viable yeast to work with.
Cropping after Primary
The main reason to crop and save your yeast after primary fermentation is that the yeast will be fresher and closer to the original culture.
The downside is that this yeast will be much fuller of trub, the brown sediment left over after filtering out your beer, or racking it to secondary fermentation.
Cropping after Secondary
Which is why many brewers find it easier to simple wait to crop until after secondary fermentation. You will find less trub than in primary, so you can simply rack your fresh wort right on top of the cropped yeast cake.
Cropping Process
In either case, you will want to be sure you are fermenting in a conical vessel so that you can drain your beer out of the bottom, into your secondary vessel, and allow your trub to collect at the bottom of the vessel.
Allow a few hours for the trub to settle, and you will notice three layers appear.
The bottom is dark brown trub.
The middle layer is your white, vital and viable yeast.
The top layer is your slurry floating on top.
You want to crop from that middle layer.
To do this, simply scoop out or allow to drain out the trub until you get to the white stuff.
Collect that into a secondary, sanitized, container, leaving off as much of the slurry as possible and allowing it to drain out as well.
Next, you will rinse your yeast to get rid of any remaining trub or slurry.
To do this, add sanitized water to the container with your yeast and swirl it around, then allow it to settle.
Your yeast will settle on the bottom, with any trub at the very bottom, and your slurry will settle on top.
Crop again as you did before.
You can repeat this process as many times as necessary until you feel you have a bright white yeast to pitch.
Then, you can pitch immediately, or you can store it in a sanitized container in the refrigerator for up to 4 to 6 weeks. Some brewers even store it for twice that time.
Cheers!
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