Fermentation Information

Questions and answers about fermentation.

like0

Comments

Re-pitching

Walter Hodges's picture

Who re-pitches/re-uses their yeast?  What technique do you use to clean it, if any?  I'd like to get a discussion going and maybe we could work up an education session on the topic.

like0

Re-pitching

Jimmy Orkin's picture

I have repitched yeast once. I use Jamil's yeast rinsing procedure. It involves collecting yeast from the bottom of your fermentor and mixing with sterile water. You let the mixture settle and collect the creamy white colored yeast.

I do not know how much yeast I re-pitched but I think you can deduce that with experiance.

The original yeast came from the Dortmunder I did well with in 2014. The re-pitched beer was the Pilsner that also did well in competitions.

Jimmy

like1

Re-pitching

James Smith's picture

I did this some back in 2014 with no problems...I had good starters and no problems with fermentation.  If you brew regularly and with the same yeast, it can be quite useful.  Also, it is useful with yeast that is not available year-round.  I used the method from Beer Geek Nation...he's a good follow by the way.  

https://www.youtube.com/watch?v=lPYUFJ4bPD4

Not to disuade anyone from doing it, but you must be very confident in your sanitation practices.  This is the main thing you are responsible for over buying commercially packaged yeast.  Also, you can not be too worried about the specific number of yeast cells you have since you obviously have no idea.  Maybe there's a method to calculate?  Other than that, it's fun and convenient...just do a starter from it and pitch.  I might do it some more this year with the amount I am brewing.  An education session would be great.

like1

Repitching (a rant)

I do this almost every time I brew for two reasons; I'm cheap and I'm lazy. It costs about $7 for liquid yeast and then you generally need to make a starter (especially if you make lagers if you are doing it correctly). Let's say for sake of argument that you have invested about $10 for the yeast alone after making the starter. To the extent you can reuse the yeast two or three times you can reduce the cost per batch in a meaningful way and really there is little work involved. Cheapness aside though the main reason I do it is to avoid screwing around with making a starter. As noted above you need a lot of yeast to make lagers (I generally make up a 3+ quart starter for a 5 gallon batch, normal O.G. beer). If you under-pitch a lager you'll likely get off flavors (from stressing the yeast) and under- attenuation (yup, been there, done that, got the t-shirt). If I am using the yeast only twice I generally pour off the layer of crap on top but don't even bother cleaning it and so far have not had any problems, more than that and I would do what Jimmy discussed above. Doing this does however require some "production planning" but for me I can tell you 6 months ahead of time what I am going to brew so it's no big deal. Now that I have 3 beers in process I am going to start lager production for the Limbo and if I do it right I can do all three batches (which is the current plan) with one yeast purchase.

Now for some "soap box pontificating"; in my opinion, the most important thing in homebrewing is running good fermentations (and all that entails) assuming good sanitation. Besides temperature control, pitching the proper amount of yeast is paramont if you want decent tasting beer. Because reusing yeast allows for a larger pitch I think doing this will help the neophyte improve the quality of his/her beer. The only beer I under-pitch on purpose is Weisebier (but then of course I am trying to maximize fermentation by products).

like2

Repitching Question

Walter Hodges's picture

So when you repitch, you mentioned that you "pour off the layer of crap".  I assume that means the dregs of beer.  So then you pour what remains in your carboy into your new beer, not worrying about the load of trub that is in there?

like0

I don't just dump the new

I don't just dump the new wort on the yeast cake, I should have been a little clearer. I usually pull the fermented beer off the yeast then put what is left in a gallon wine jug I use for growing up yeast. Since everything gets pretty stirred up doing that I let everything sit for maybe a day. At that point things separate and generally there is some crap on the top of the yeast then underneath that is a layer of putty colored stuff (the yeast). I pour off all the liquid as well as the crap leaving the yeast. Just to get it out of the wine jug I run in some new wort then stir the whole thing up so I can pitch it directly into the new batch. I guess I should add that if it sits around more than a couple of days it might be worthwhile to feed it a little wort to get it going again before pitching into a new batch 'cause especially with lager yeast you want healthy, fully active yeast so fermentation takes off right away. I have had lager yeast throw up a 3 inch head of krausen in a couple of hours with the second generation which I see as a very good thing. 

like1