Yeast Harvesting

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davidkrau

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What am I doing wrong? I tried to harvest yeast from an All Grain Kolsch brew. After I siphoned the wort from the primary fermenter into a secondary I poured about a quart of previously boiled and cooled water into the primary fermenter, swirled it around and poured about a half quart into a quart bottle added water that had been boiled and cooled. I swirled it around,let the dregs settle out and poured the cloudy upper layer into another bottle, added water let it settle out and again poured the cloudy layer into a sanatized beer bottle.capped it and refridgerate it overnight. I then made a starter which was was 1 pint of water and 1/2 cup DME. I boiled and cooled boiled the starter, pitched the yeast that I had previously harvested put an air lock on the bottle. AFTER 5 DAYS NO SIGN OF ACTIVITY IN THE AIRLOCK AND NO KREUSEN. WHAT DID I DO WRONG?
 
Sounds like you allowed most of the yeast to escape! Although you want to eliminate the trub by letting it settle to the bottom, there should be a pretty nice layer of yeast that collects above the trub. You want to get that yeast into suspension before decanting the "cloudy layer." It sounds like you kept pouring the fermented beer off of what might've been a viable yeast cake. Now, I doubt you've eliminated all of the viable yeast in your harvest, but you've probably harvested relatively little, and you got the least flocculant yeast of the whole batch (not that Kolsch yeast is particularly flocculant anyway).

To fix it, let it settle, pour off the starter beer, add some fresh wort, and try again. Step it up like that at least once more, and I bet you'll notice some activity.

On the other hand, sometimes yeast starters ferment so fast that you hardly notice any activity at all. Again, step it up like I described above and see what happens.
 
This is a little off the subject but related. I am getting ready to try the batch I just harvested. I used the same process but I poured all of the mix into a gallon jar that had been sanitized. I then swirled it good and allowed it to settle maybe a half hour. I carefully poured the suspended mix into a quart jar, and repeated the process with that mix. As soon as it settled out I poured the suspended mix into a third jar. This is the portion with the yeast in it. Cover it and refrigerate. It will settle again, the portion on the bottom is the yeast. To use it pour out the liquid on top and use only the bottom.
Now my question... I also have some wort from my last batch but it is a llittle high on gravity. I have read about 140 is good for a starter. Can I just add sterile water to get the gravity down to 140, boil that and use it for the starter?
 
I think Yuri got it right, you washed most of the yeast away and got just a small amount into your final starter. The cell counts are low and it will take time for the yeast to increase in numbers as well as any bacteria along for the ride.

Next time you do this, keep in mind that all you are trying to do is reduce the amount of trub you carry into your starter, not eliminate it. As homebrewers, we do not have the equipment to remove the trub as effectively as we would like.

I repitch my yeast regularly from my primary fermentations and they seem to grow fine in my starters. Here is what I do and, keep in mind, everything I add to yeast has been boiled for 10 -15 minutes and cooled in a covered stainless steel pot and all containers have been sanitized.

1. After removing my fermenting beer into a carboy, I leave a little beer in the bottom of the bucket so the yeast, trub, etc is the consistency of flowable mud. I pour this into a half gallon plastic container. This saves me from using sterile water. The container is the plastic containers my LHBS uses for selling liquid extract.
2. Often, I put this collected slug into the refrig until I am ready to make a starter which may be a week or two, no more.
3. To make a starter I add sterile water to the slug, about a quart or so, swirl well, wait about 1 -2 minutes (the big chunks will settle in that time) and then carefully pour about 2 inches of liquid into a one quart mason jar. This is my harvested yeast. To the mason jar I add my sterile wort, add an air lock and let them go overnight. I throw away the remaining container of slug. You will get fresh yeast once you new fermentation has completed primary fermentation.

I only reuse my yeast like this about 3 -5 times, then I buy new yeast.

I hope this helps.

Dr Malt
 
I wonder if anybodyd did acid wash for harvested yeast? It suppose to kill all the bacteria (well, not all of it) with low pH.
 
I don't bother with an acid wash for my yeast. I feel confident that my santitation procedures are good enough to get a decent yeast harvest for at least 3 batches, if not a few more. Like Dr Malt, I don't like to reuse yeast more than that because it mutates and can become impure with wild yeast, even with the best sanitation. You wouldn't kill wild yeast with an acid wash, but you would certainly remove the majority of any bacteria.

If I were to acid wash, I'd probably use Star San or food grade phosphoric acid to lower the pH of distilled water. Suspending the yeast in a solution with a pH of 2 to 3 for a few minutes should be all that's required, but you'd probably need to leave it in the acid solution for longer to let it settle out. Then you could pour off the acid and add starter wort or water as desired.
 
I think I'll give it a try. I made starter last week but had to put on hold my brewing session till next week. I also got tartaric acid from LHBS. I think I'll try to wash it and then make starter with it again. If it behaves well - will use it for my next batch. Thanks for the info.
 
I always aerate my starters. In fact, I use a stir plate that provides constant aeration. Remember, you don't care what the starter tastes like, you just want to propagate yeast, and they need oxygen to reproduce.
 
I want to thank everyone for for responding to my thread. I'll try harvesting yeast again following your suggestions. Thanks Again.

David Krause
 
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