Yeast Management in Brewing
The challenges of yeast management in brewing can be as simple or as complicated as you let them be.
In reality, yeast is a very cooperative organism that actually wants to be helpful, when you think about it.
And it does not take much to harvest it, crop it, bank it, or store it, so that you can grow a happy following of beer drinkers excited to experiment along with you.
First, let’s look at the power of yeast in brewing.
Yeast in Brewing
For thousands of years, brewers have drawn on the wonders of yeast as a miracle.
Anthropologists tell us that the first “brewer” was like a woman who was harvesting her grain and got caught in a sudden rainstorm.
She hurried to take cover, leaving her grain out in the rain for several days before she could return to it.
When she did, she would have found soaked, soggy grain, covered in fresh rainwater.
Never one to waste resources in those times, she would have kneaded that grain and turned it into bread, which rose delightfully in the oven and provided a lighter fluffier bread than the family was used to.
And she would have served the rainwater to her family, trusting it to be fresh and safe.
Little did they know that the euphoric effects of that rainwater were due to the fermentation process elicited by the naturally occurring yeast in the air.
The alcohol content would have been very low thanks to the high starch content and relatively low sugar content in the grain.
Thanks to yeast then, from that point on, that family, and every family that woman told, would be able to offer a fresh, safe, nutrient rich beverage alongside each meal to their whole family, which was a much better alternative to the potentially toxic running river water.
Over time, of course, brewers picked up on this wonder and began to offer this beverage in their inns. They got savvy to the fact that roasted, now called malted, grain was more sugary and would provide a higher alcohol content, but the process was much the same for millennia.
Malt grain, grind it, boil it in water and steep it, and then leave it out for the fermentation process to take place.
Eventually, brewers caught on to the fact that the clumping formations on the top of their brew were responsible for the fermentation process, and they began to harvest it.
That was the beginning of yeast management.
Yeast Management in Brewing
Because yeast is and has long been so happy to do its one job, find sugar and convert it to alcohol and carbon dioxide, it is quite easy to manage.
You can buy it from a manufacturer, crop it yourself, grow it, collect it wild, bank it, and store it.
You can do any one of these things or all of them.
Buy Yeast
The most common beginning for many brewers is simply to buy yeast from a manufacturer. You can buy it dried or wet, just know that you will have many more options in terms of strains and varietals in wet form. It takes extra steps to dry and package yeast than to simply offer it live and active.
Many brewers begin with dried yeast as they practice their craft and then experiment from there.
Dry yeast is also easier to store and will remain shelf stable for years, whereas with wet yeast you have several months if you store it properly.
Crop or Harvest Yeast
Another option is to crop yeast, either from your existing brew at the end of fermentation as brewers of old have always done, or even directly from the bottle, if you find a beer that you love.
If you have a favorite beer and want to work with the yeast that made it, you can collect the bottom of the bottle once you have poured the beer into a glass. Do this with three or four beers to ensure you have enough yeast, and then rinse it to get rid of all the slurry and get the purest yeast possible for pitching.
Then, you can pitch that yeast into your wort to see how it performs. If you like it, you can continue to crop the yeast after primary or secondary fermentation and continue to use it.
Grow Yeast
Many brewers also like to grow their own yeast with yeast management tanks, which will keep yeast happy and fed and ready to pitch.
This takes a lot of equipment and really only makes sense if you have a large scale commercial production, but if this is you, it is worth the investment to have your own large stores of yeast for constant pitching.
Wild Yeast
More recently, brewers have harkened back to the old ways of doing things, either collecting yeast from plants in the environment, or simply allowing the natural process to occur, leaving the wort out exposed to the elements, with a light covering to keep out sediment.
Your wort will ferment, all good bacteria and yeast attracted to your wort will kill off any bad bacteria during fermentation, and you will have the closest thing to a local, native ale or lager you can imagine.
If you like the result, you can harvest the yeast and repitch it or store it.
Bank Yeast
Craft brewers also like to keep yeast banks, wherein they store small amounts of yeasts they love in vials for months at a time, which you can do with great refrigeration or even freezing if you are careful.
In the end, dry yeast will store on a dry, cool shelf in an airtight container for many years, and wet yeast can store in a refrigerator in an airtight container for several months.
You can even freeze yeast for several years if you are careful with your packaging and don’t mind losing a percentage of viability to frostbite.
The trick is to always keep an accurate measurement of viability, so be sure to have the proper equipment on hand.
That way, you will know your viability percentage and can get an accurate pitch rate every time.
Cheers!
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