Yeast Rinsing

[Benniee]

Hello All,

I'm a long time listener/reader from Australia - first time poster to your forums.

I've got a question for all the yeast experts out there related to rinsing of some yeast I collected after an Oktoberfest ferment. I've been attempting to rinse the yeast to remove/reduce the trub and dead yeast cells before repitching it.

Today I managed to take a few pics of the process, and I'm a little confused about the settling and separation I'm seeing. I've attached them below (I hope they're not too large for anyone on a slow connection)

First up - added around 1 parts slurry to 3 parts cooled, boiled water. Shaken for around 30 seconds.


You can see that the mixture has definite clumps of material in it. The beer it came from didn't get any break material transferred into the fermenter.

Next up is around 3 minutes later. There is some separation starting to happen. Again the clumping is visible.


5 minutes in now and the separation is more defined.


10 minutes now and I'm starting to see a new layer of something settling out.


Now I'm not completely new to yeast rinsing, and I'd normally be looking for a separation around the 10 minute mark - but is everything that is settling out prior to this really trub/break/dead cells??????? It looks a creamy colour just like healthy yeast. And if I decant the liquid off at around the 10 minute mark I end up with very little yeast - around 50mL from the yeast cake of a 12L (or 3 gal) beer.

I have posted this thread on one of our Aussie forums and I have a discussion about it going on there - I'm just interested to hear the opinion from some of you guys on what's going on.

Is it possible that the material settling out in the first 10 minutes is yeast?
If I'm not getting a lot of yeast from the rinsing process, am I not breaking up the yeast/trub effectively enough when I shake?

What do you think?

Benniee

[Stinkfist]

you want the stuff on the top....the hops and trub and dead yeast will settle out first, you want the healthy yeast on the top..

[Benniee]

Yep - I know the usual routine for rinsing yeast - removing the liquid off the trub. But looking at the photos I posted up the material that settles out in the first 10 minutes looks remarkably like good yeast, and not the look of trub that I'm used to.

Benniee

[Stinkfist]

Maybe because it is an Oktoberfest which are usually lightly hopped, maybe that is why it looks so clean at the bottom? You do not want the stuff that falls out quickly anyways...there should still be plenty of yeast in suspension, and that is the yeast you want.

[positiverpr]

if there are any big chunks in the very bottom then you dont want that. i had the same issue as you did when i first starting rinsing. if the top layer(not the liquid) was the only viable yeast then by your pictures you would not have much yeast. i think that your good pitching most if no all of that bottom layer.

[EagleDude]

I am far from an expert on yeast rinsing, but I know what has been working for me. I take a quart nalgene bottle and fill it 3/4 full of yeast cake, seal and place in the fridge until ready to use (2-3 days). As I am filling my carboy with cooled wort, I poor ~1/2 of a crap beer (budweiser and the like) into the nalgene, shake, and wait ~10 minutes. I get the separation much like your pictures. I poor off everything above the real thick bottom layer into the wort and aerate (One nalgene per 5 gallon fermentor). The results have been great with really quick starts to fermentation, clean beers, and depending on mash temps always in the 1.010 area +/-. Although I haven't looked in a microscope to count cells, I would guess that, despite the small volume of liquid yeast slurry, the density of yeast cells is probably quite high as compared to a standard starter.

[Benniee]

Ok - thanks for the input guys.

So in short - don't let the colour of what is settling out fool me - it's still trub, and just harvest the liquid off the top once the first layer of stuff has starter to for a clear layer line.

In the past when I rinse yeast it's been relatively easy because the first shake/mix looks like an even mix of stuff, and it takes at least 10 minutes to see any sort of separation hapenning. This last one just looked completely different.

Benniee

[a10t2]

It looks like you have three fairly distinct layers, which is what I typically see. The first, thin brownish layer at the bottom is primarily dead yeast - they settle out quickly because once they die water gets pulled out of the cells and they shrink, making them more dense. Then you have a nice thick layer of off-white healthy yeast, and finally on top there are the smallest particles - break materials, miscellaneous proteins, bits of hops, etc.