Reusing Yeast.

[AndrewC5]

Tried asking this a while ago but never really got a good answer, if i wanna reculture yeast from one batch to the next can i bottle the first beer then put the wort straight onto the yeast cake at the bottom then mix it in, or do i need to extract it and let it settle over night? if i do wanna let is settle, is the yeast the think stuff at the bottom of the dense liquid at the top?

[BrianS2]

I rack the beer into a bottling bucket first.

I just pour the wort over the yeast cake and reuse the same fermenter. Ferments very quickly and makes good beer.

Or you can wash the yeast if you like!

Done both ways.

 

[AnnM]

Brian - when you do this, can you just cool your boil down (usually 2-3 litres), pour that on top of the yeast cake and then proceed to fill up to the 23L mark? And do you end up with a really thick yeast cake after the second brew?

[BrianS2]

Hi Ann

I have plenty of spare buckets and fermenters. So i make up the wort in another fermenter check the temp is OK and transfer the work across to the yeast cake (fermenter). If you have only one fermenter then you need to wash the yeast with 1-2 litres of water and transfer into a jug or small plastic container. I sometimes use a 3 litre juice container to hold the washed yeast in the fridge for 1 or 2 weeks between brews. Pour off the surplus water from the settled yeast and add to wort. Do a google search on washing yeast. It's easy to do. I reuse yeast 2 -3 times. Normally use US-05 is good clean yeast.

Brian

[BrianS2]

Thick yeast cake after second fermentation.

No - not really. You can wash and divide the yeast so as not to over pitch the wort. But I dont bother. Fermentation starts within 30 minutes or less and ferments out in 2 days. Although I leave it in the fermenter for 10 day or more.

And keep the temp low.

[THIRSTY MATT]

Paul,

im interested in what you'd say about the above if you get time??

i would go the way of putting yeast slush in a sanitized 2 litre coke bottle then repitchin, either on the day or id put it in the fridge for later.

cheers

matt

[AndrewC5]

how do u repitch? just chuck the slurry in and stir weel, or do u need to do something first?

[AnnM]

Hi Ann

I have plenty of spare buckets and fermenters. So i make up the wort in another fermenter check the temp is OK and transfer the work across to the yeast cake (fermenter). If you have only one fermenter then you need to wash the yeast with 1-2 litres of water and transfer into a jug or small plastic container. I sometimes use a 3 litre juice container to hold the washed yeast in the fridge for 1 or 2 weeks between brews. Pour off the surplus water from the settled yeast and add to wort. Do a google search on washing yeast. It's easy to do. I reuse yeast 2 -3 times. Normally use US-05 is good clean yeast.

Brian

 

Thanks Brian. I have actually done it that way (washing the yeast); however you originally said you "pour the wort over the yeast cake and reuse the same fermenter" (above), and I thought "Hey that would be super easy". I can't see why you couldn't just cool the boil down, add some cold water to it and then pour it on top of the yeast cake in the same fermenter and fill up. After all, the fermenter should still be sterile and shouldn't need washing and sanitising again. Can anyone see any reason why this wouldn't work? (I'm pretty lazy you know!) [innocent]

 

[AnnM]

Confusion time! I just Googled "washing yeast" and here's what I got:

 

"Step 1: Harvest the Yeast

 

After racking the beer off the yeast in either the primary or secondary fermenter, swirl the container (carboy/bucket) until all the yeast is in suspension. If there is not enough liquid to achieve this add about half a cup of the sterile water to the fermenter to loosen it up. Dump this into one of your sanitized mason jars, cover with cling wrap, and secure the wrap with a rubber band. Put this into the refrigerator for 20 min to 1 hour (depending upon how cold the initial slurry was).

 

Step 2: Separation of the Trub from the Yeast

 

After being in the fridge you will see a separation of the components of the slurry, something like below. [The diagram obviously doesn't show here.]

 

 

The hardest part to see is the thin line of yeast between the trub and the liquid above. When your solution looks similar to the diagram, carefully pour off the suspended yeast into a sanitized mason jag and leave the trub layer behind. The thin layer between the two contains yeast, but don\u2019t worry about collecting it, there will be plenty in the suspension provided the solution has not been sitting in the fridge so long as to allow the top to become clear."

 

The puzzle is: Many posts advise to pour off the liquid on the top and re-pitch what's left on the bottom. But according to these instructions (and others I've read), you should use the liquid on the TOP and discard what's on the bottom!! [pinched]

 

Which is correct?

 

 

[AnnM]

Here's a link to a really easy to understand process - which answers my question above: Yes, you do use the liquid off the top and leave behind the trub on the bottom.

http://home.comcast.net/~wnevits/wizards/yeast_washing_rev_5.pdf

[PB2]

Paul,

im interested in what you'd say about the above if you get time??

i would go the way of putting yeast slush in a sanitized 2 litre coke bottle then repitchin, either on the day or id put it in the fridge for later.

 

Dropping a new brew straight onto the yeast will get fermentation going, for sure! After all, a fermenting brew is a yeast farm [cool]

 

However, I like to remove yeast and then pitch onto a brew in a cleaned/sanitised FV.

 

One could argue that a similar layering effect, as described by Ann, occurs in the FV. With this in mind try this techique:

1. Draw off all but about an inch of fermented brew from the FV.

2. Pick the FV up and swirl the reamining liquid enough so it gradually becomes more milky but enough to crack the bed of slurry. A degree of patience is required here

3. Draw the milky liquid off into a sanitised jar, seal and place in the fridge until you are ready to use it (will easily keep for a week).

 

When ready to use, swirl the contents of the jar to make a milky mixture again. patience again

Smell it to make sure it's okay and pitch on the new brew, leaving some solids behind.

 

This technique may not work so well if there is a large amount of hop ddebris, etc. in the former brew and you don't want any carried over into the next.

 

Also, every cycle increases the amount of wild yeast and bacteria.

[AnnM]

That sounds nice and easy Paul! Thanks.