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Reusing Yeast

H

Hop Head

How can I safely reuse yeast from one batch for the next batch?  Won't it get contaminated?
 
It will get contaminated if you're not very careful about sanitization. But, if you take extra precautions (such as spraying your work area with StarSan or Iodophor, flaming the lip of the yeast container, etc), you shouldn't have any problem.

How you harvest will depend on what you're fermenting in. But, the basic procedure is to transfer your beer to secondary, leaving a bit behind -- a pint or so is enough. Then swirl the fermenter to get the settled yeast back into suspension and pour it into a sanitized glass container. I use Erlenmeyer flasks, some people use glass canning jars, some use juice bottles, etc. Then cover the top of the container with several layers of aluminum foil -- I usually just take a big piece and fold it over twice. You can sanitize the foil if you like or just use it from the box (assuming the box hasn't been dragged though the dirt or something). Then put the yeast in the fridge -- make sure it doesn't freeze. If you use it within a week or so, you can just take it out, pour out the liquid on top, and pitch 300-400 ml (1.25-1.75 cups) and stand back! You'll see the best fermentation you have had!!!
 
I do the same with the following precautions...

I store the yeast in beer bottles (well sanitized) that I fill about 1/3 full of wort, then add the gunk from the fermenter to get a nice starter.

I put a stopper and airlock on mine and let them sit for 12 hours or so until they are fermenting actively.

Then I pop them in the fridge and store them - often for several months.

When I'm ready to use them I warm it up and immerse the whole bottle up over the cork in water with iodophor - that sterilizes the outside of the bottle to avoid accidental contamination when I uncork it and dump it into the fermenter (or another starter).

Cheers!
Brad
 
When I'm ready to use them I warm it up and immerse the whole bottle up over the cork in water with iodophor - that sterilizes the outside of the bottle to avoid accidental contamination when I uncork it and dump it into the fermenter (or another starter).

No need to warm up yeast from the fridge, if you use it within a week or so of harvesting. Just keep it in the fridge until you're ready to pitch, pour off the liquid, and pitch about 300-400 ml of the thick slurry. I've been cold pitching for over a year now and have had nothing be great results, as have many other homebrewers that have tried the method.

And, before someone says that the yeast will be shocked, that's true when you pitch warm yeast into cold wort -- cold yeast in warm wort is no problem. In fact, the yeast love it!
 
how many times can you do that with the same yeast.and could you just through a new wort into a primary bucket a soon as you sifon it into a secondary.just put right on top of the yeast from the last batch.
 
I usually start with a clean bottle of sterile wort each time, but I have reused yeast up to 4-5 times before buying a new sample.

Brad
 
took some sediment  from bottom of primary on my last batch and put it in a couple of beer bottles,took it out of the fridge poored off the top liquid and pooted the slurry in some warm water for 20 minutes then put in a teaspoon of corn sugar,nothing really happend like when your rehydrating yeast i stirred it once after a half hour and it foamed up all over the place.i was just screwing around seeing if i could get it started again didn't seem like it was working to well.was i doing right or what.
 
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