First time pitching with washed yeast

[Andy Brosius]

I recently harvested (washed) some S-04 from a batch of robust porter. I've created a starter and saw a bit of activity overnight. I've taken it off the stir plate, will let it sit for about 12 hours, then will cold crash overnight before my brew day tomorrow.

My question is: how do I know how much to pitch? I know the only way to know for certain is to count under a microscope, but what are the general guidelines here?

Thanks!

 

[VikeMan]

My question is: how do I know how much to pitch? I know the only way to know for certain is to count under a microscope, but what are the general guidelines here?

How much slurry did you use in the starter? How dense was the slurry? How clean (free from non-yeast particulates) was the slurry? All these factors will influence the final cell count.

 

[Andy Brosius]

I think I've probably done something wrong. I was worried about excess trub getting into the new batch, so I shook the two pint jars and allowed them to settle for 20 minutes before pitching, leaving most of the slurry behind. I'm fairly certain I read that in How to Brew, with the idea being that the healthiest yeast would remain suspended after a shake, while the trub/less vital yeast would settle out. I don't have time to track down the passage at the moment, though.

Actually, one of the two pint jars I pitched today was from a previous starter I'd done with the same harvested yeast. It failed to show the kind of activity I'm used to seeing, so I didn't feel comfortable brewing with it.

When pitching tomorrow, I was going to pour off most of the liquid, and then pitch the remaining slurry (again following Palmer's instructions).

Your thoughts would certainly be appreciated.

 

[VikeMan]

It sounds like you shook some yeast into suspension, allowed a lot (most?) of the cells to settle out, then used the remaining suspended cells in the starter. I can't say I've ever seen it done that way.

I suppose that after you crash the starter, you can eyeball the yeast cake and mentally compare it to past starters to get a feel for what you got.

 

[bernardsmith]

I think that you raise a good question for those of us who rarely (if ever) used harvested yeast. Here's my very limited experience and I may be mistaken.

A short while ago I harvested some yeast from some wine I had been making, and assumed that after allowing the sediment to fall the yeast was in suspension and so I poured the liquid into a carboy into which I had added some fruit juice. No activity.
My next experiment was to harvest another batch of (indigenous) yeast and after washing, I allowed the lees to settle for about 30 minutes or so, I decanted the water and washed the slurry a second time and again allowed the lees to settle, this time for about two or three days. I had made a must from some whey to which I added lactase and some sugar) and decanted the liquid and poured in the slurry and voila! Success!! Bottom line: the trub (in your case) is heavy and settles first, the yeast settles above the trub if you agitate and wash it in enough water, so you want to remove the yeast from the trub by shaking the sediment and allowing the sediment to crash for a short time to ensure that the trub settles out first, then you decant and save that liquid which is essentially yeast and water with very little trub and you then allow this to crash for a couple of days so that the yeast settles. The "trub" is going to be darker than the yeast and the yeast tends to be very light colored so you should see lines of demarcation getting lighter and clearer the higher up the container you look , with the top of the container being water.

 

[Andy Brosius]

It sounds like you shook some yeast into suspension, allowed a lot (most?) of the cells to settle out, then used the remaining suspended cells in the starter. I can't say I've ever seen it done that way.

I suppose that after you crash the starter, you can eyeball the yeast cake and mentally compare it to past starters to get a feel for what you got.

I think that's exactly what I did. Thankfully, there appears to be a pretty substantial amount of slurry at the bottom of flask, so I think I'll have enough to brew.

 

[Andy Brosius]

Bottom line: the trub (in your case) is heavy and settles first, the yeast settles above the trub if you agitate and wash it in enough water, so you want to remove the yeast from the trub by shaking the sediment and allowing the sediment to crash for a short time to ensure that the trub settles out first, then you decant and save that liquid which is essentially yeast and water with very little trub and you then allow this to crash for a couple of days so that the yeast settles. The "trub" is going to be darker than the yeast and the yeast tends to be very light colored so you should see lines of demarcation getting lighter and clearer the higher up the container you look , with the top of the container being water.

Thanks, bernard. That was more or less my understanding of it, and there were clearly demarcated lines of yeast and trub as you say.

This starter appears to have been successful, but now I'm wondering if, when pitching the starter, I should apply the same principle and try to leave as much trub as possible behind? Typically I pitch the entire remaining slurry, but is there any reason why we couldn't try "wash" the yeast here, too?

 

[bernardsmith]

I would think that if you are brewing beer the trub is likely to contain both parts of the beer and hops that you may not want in a subsequent brew. I make wine and a tiny amount of fruit in the lees may or may not be a problem (although if the wine from which I harvest the yeast is red and the wine I am making is white I don't want any of the color from the previous wine to discolor the current one... So I certainly try to wash and remove everything but the yeast, knowing that (as far as my technique goes) I am likely to lose a percentage of the yeast in the sediment.

 

[Andy Brosius]

Healthy krausen forming after ~14 hours:

 

[Brewmasher]

I think I've probably done something wrong. I was worried about excess trub getting into the new batch, so I shook the two pint jars and allowed them to settle for 20 minutes before pitching, leaving most of the slurry behind. I'm fairly certain I read that in How to Brew, with the idea being that the healthiest yeast would remain suspended after a shake, while the trub/less vital yeast would settle out. I don't have time to track down the passage at the moment, though.

Actually, one of the two pint jars I pitched today was from a previous starter I'd done with the same harvested yeast. It failed to show the kind of activity I'm used to seeing, so I didn't feel comfortable brewing with it.

When pitching tomorrow, I was going to pour off most of the liquid, and then pitch the remaining slurry (again following Palmer's instructions).

Your thoughts would certainly be appreciated.

Its pretty hard to screw up a homebrew. If you had enough yeast to make a starter, you have enough to ferment. I don’t even wash harvested yeast. I just scoop off a good amount of trub, and top it off with sterile water in the fridge. Trub is yeast nutrient. Some people wash off all the trub, and then buy nutrients to add??? I don’t even make a starter when pitching harvested yeast. I harvest enough yeast to make at least 10 batches, maybe only 5 if they are high gravity. Just cool off some wort and add it to your yeast while you do your boil, pitch when ready.