[tom2001d]

How long do I need to wait after harvesting and washing the yeast before I can pitch it into a new batch? I am planning on bottling a batch on Saturday. Can I wash the yeast on Saturday and have it ready for a Sunday brew? This is my first time harvesting and I know I should use a starter. Could I do that Sunday morning and brew Sunday afternoon?

Lots of questions but I just don't want to screw it up.

[Jimmy K]

I don't think there is any minimum time it needs to sit. After washing it could be pitched immediately.

[Joe Sr.]

The sooner the better on a repitch.  Saturday to Sunday would be just fine.

Re-using it that soon will not require a starter as long as you pitch enough slurry.

[morticaixavier]

don't even need to wash it really.

[klickitat jim]

Given that many people just pour the wort right on top of the old yeast cake in the used fermentor,  you'll be fine. The problem is getting your pitch rate right. I estimate and then forget about it. If you look at Mr. Malty, and guess a low concentration of cells to be safe, and a high percentage of non yeast to be safe, then about 300ml of day old unwashed slurry is fine for 5 gallons of 1.060 ale. That's about a cup and a quarter.
What I'd do (just did this morning actually) is rack my beer off the cake. Leave a 1/4" of beer. Swirl that slurry up till there's none stuck to the bottom. Pour that into a sanitized quart jar and put it in the fridge. When you're ready to pitch just pour off the beer at the top and pitch a cup to a cup and a half of the yeast. Cup if you're wort is 1.040-60 cup and a half if over 60. If it's huge, like 1.070 or bigger you'll need more. Double if it's a lager.

This is the Klickitat Jim scientific method dumbed down to reality in the homebrew world.

[Joe Sr.]

Your scientific approach is very close in method to my random estimation approach.

I use tupperware containers, however, not jars.

Unfortunately, I am rarely able to time my brews that close to packaging these days so I'm repitching older yeast.

[klickitat jim]

Joe, lately I've been brewing with 1056 exclusively,  so that helps on keeping things fresh. If I was rotating through a few different varieties that would mean I would be doing starters a lot more. As a house rule, if my used yeast is more than a week old I run a starter with 100ml yeast and 2000ml of 1.035

[Joe Sr.]

I use a starter every time.  It's been quite awhile since I've gone with an immediate repitch.  Over a year, for sure.

Of course, I pitched dry yeast on Sunday because it was easy.

[HoosierBrew]

My "scientific" method is similar to both you guys (Joe and Jim).  I regularly get fast starts and good attenuation, so I think I'm definitely in the ballpark.

[klickitat jim]

My general method is not not freak out about details like... it calls for 238ml of yeast but I used a cup and a half LOL
I have to start with the fact that I don't brew with a microscope.

[HoosierBrew]

My general method is not not freak out about details like... it calls for 238ml of yeast but I used a cup and a half LOL
I have to start with the fact that I don't brew with a microscope.

I totally agree !