Yeast Harvesting from a bottled commercial beer

[Mase]

So looking for inspiration for our next stout recipe, my wife picked up a six of Bell's Kalamazoo Stout. I noticed sediment on the bottom of teach bottle, and am assuming its yeast (Beer was fresh) as the beer probably wasn't filtered.

So tonight, we will down a couple Kalamazoo stouts and attempt harvesting the yeast. Yep... chasing a squirrel! Never harvested yeast from post fermentation, or from a yeast starer or anything of the sort. So the thinking is to harvest the yeast to be used in a not yet determined stout recipe. Why you might ask, well.... Primarily to experiment with yeast harvesting, but if all goes well, might just pitch into a simple stout and see how it goes.

Obviously the emphasis will be more abut yeast harvesting, with the added benefit of snagging the yeast from a commercial beer to see if we can grow the culture, with the secondary benefit of brewing another batch of stout.

This leads me to my question to see if my approach seems sounds or not:

• Open the bottle and gently pour the Kalamazoo stout into a glass, leaving behind a half inch to an inch of beer;
• Starsan the mouth of the bottle (outside only);
• wrap in Starsan sprayed plastic wrap;
• Shake the contents well to get the solids/yeast into suspension;
• pitch the contents into a cleaned and sterilized flask with 1 quart of DME based yeast starter of DME at 1 cup DME to 1 Quart water.
• Place on a stir plate for 24-48 hours.
• After stir plate, take flask off stir plate and cover and place in the fridge to allow the solids/yeast to settle;
• Decant liquid and replace with sterilized spring water, give a good shake;
• Pout into sanitized Mason jar for storage.

Looking for any good feedback.

 

[Nosybear]

There's nothing wrong with your procedure, if it's a bottle-conditioned beer, whatever yeast they conditioned with should grow and prosper. You'll want to build up the starter by increasing the amount of wort by 10x each step. If you have a ml of yeast, your first step will be 10 ml, then 100, and so forth. Now the bad: The yeast in the bottle is not likely to be the yeast that fermented the beer. Breweries are very protective of house yeasts, often filtering or pasteurizing the beer before repitching with a conditioning yeast to protect their proprietary strains. This may not be the case at Bell's, but it may. So don't be surprised if your results are different than Bell's.

 

[HighVoltageMan!]

1 quart of DME based yeast starter of DME at 1 cup DME to 1 Quart water.

If you do any starter with this formula, you will end up with about a 1.080 starter. Way too high of a gravity for any starter. Shoot for 1.35-40, which requires @ 1/2 cup of DME per quart/liter.

your first step will be 10 ml, then 100, and so forth

This is solid advice. Keep your starter gravity @ 1.030 for the first step. Then use the standard 1.035-40 for the rest of your steps. You want to give the yeast a fighting chance against bacteria, mold, ect. By starting out small the yeast can dominate the small starter quicker and keep the other microorganisms at bay.

Good luck! Sounds like a fun experiment.

 

[GFHomebrew]

My only and questionable advise from what ive cleaned from forum threads and personally use in my brewery is your better to store yeast under fermented beer than water. The ph is lower and alcohol content both help to reduce nasty yeasties and prolonged shelf life.