Reusing slurry

In another thread I had mentioned how I like to pitch onto yeast cakes from previous batches, and Bob pointed out that I have been overpitching so I would like to start measuring my slurry using the mr malty calculator.

Here's how I would like to approach this: a day or two before brewing I would like to go ahead and either bottle or transfer to secondary the batch that is sitting on the yeast cake I want to reuse. I have a large mason jar that I will put mL marks on. I will dump the entire cake (including left over beer) into the sterilized jar, put the lid on, and keep in the fridge. The day of brewing, I will siphon out and dump as much of the top-sitting yeast as I need to in order to bring the contents of the jar to the proper pitching level (using the calculator). Then the jar will be left at room temp to warm up over the course of the 6-7 hour brew session.

Anyone see anything wrong with this approach?

Looks good to me............just sanitize everything!!

Nope! Just leave yourself enough space in the jar to contain the slurry and cover it LOOSELY. (I had an awful experience with a yeast fountain once. )

On brewday, you should be able to physically see the layers. Refrigeration will help this. You can try to get the mid-level stuff.

The large chunks of trub - hops particles, proteins, all that rot - should be at the bottom. Also in that layer will be yeast which prematurely settled. You don't want that gunk.

On top will be a layer of late-settling yeast. You don't want to propagate that, either, or your colony will become powdery and never clear properly.

The middle layer is what you want. If/when you get at it, it should be tan, slimy and smell yeasty. Depending on the strain, the consistency will vary; some are the consistency of pancake syrup, others quite thick. Most will look and handle like pancake batter, if that's a useful visual metaphor.

Really, though, depending on how many generations you wish to pitch, you can just stir up the whole mess and pitch the resulting slurry. I wouldn't go past four generations like that, but if you can't separate the layers, it works very well. Just increase the "Non-Yeast Percentage" to the maximum on the calculator. Then decant sufficient slurry to another sanitized container and let it warm up to pitching temperature before discarding the rest - or you could save it and make some bitchin', wicked good bread!

Cheers,

Bob

great--appreciate the info!

So I did this yesterday, and I'm not seeing much activity at all. The yeast from the previous batch sat in the fridge for less than 2 days, and settled into 2 layers - a solid layer on bottom, and a beer layer on top. I had about 1000 mL of "solid stuff". There was some hops and trub in there, so I increased the non-yeast percentage to 20%. I made 2 beers - a 1.047 and a 1.062. Bothwere 5 gallons, and the calculator said to pitch 79mL and 109 mL, respectively. I piched slighty more than this because it didn't seem like enough yeast.

So what's going on? It FEELS like I underpitched, and like I said I'm not seeing much activity after 24 hours.

I still have about 800 mL of slurry that I'm thinking about dividing up and repitching, but unless I'm missing something this calculator seems to be wrong...

I store my slurry in pint canning jars in the fridge. I write with a sharpie the milliliters up the side of the jar in 100 increments. After the yeast has settled I can roughly measure how much yeast I have or I can measure how much trub and yeast I have. If I measure yeast only, I set the calculator 0 for "non yeast" and "thick" for the slurry. If I measure the yeast and trub, I set it to the highest for "non yeast" and leave the slurry pretty thick. I've become pretty good at decanting about 100 mL of yeast into each pint jar and I pitch the number of pint jars I need to get in the ball park.

brown_dog_us said:

If I measure yeast only, I set the calculator 0 for "non yeast" and "thick" for the slurry. If I measure the yeast and trub, I set it to the highest for "non yeast" and leave the slurry pretty thick.

Click to expand...

That's what I don't get - even if I set the "non-yeast %" to the highest setting it still recommends less than I pitched, and like I said fermentation has been quite slow to this point.

Maybe I don't understand the yeast concentration setting, as that seems to provide the widest range of recommendations. I left it pretty much in the middle because I was unsure, but honestly this was a pretty thick slurry I pitched. I actually had to use a sanitized spoon to get all of it out of the jar.

So what is the recommended method for seperating these layers? Should you just use a sanitized spoon and scrape them off of each other?

maltMonkey said:

That's what I don't get - even if I set the "non-yeast %" to the highest setting it still recommends less than I pitched, and like I said fermentation has been quite slow to this point.

Maybe I don't understand the yeast concentration setting, as that seems to provide the widest range of recommendations. I left it pretty much in the middle because I was unsure, but honestly this was a pretty thick slurry I pitched. I actually had to use a sanitized spoon to get all of it out of the jar.

Click to expand...

I started measuring the layer of yeast so I could set it to 0% "non yeast". I also figured that since I was measuring the solids that had settled it was a thick slurry. I am only trying to get close to the right amount of yeast with out under pitching. I think you need to pitch a lot of yeast to get off flavors or problems due to overpitching.

Old post, not sure if anyone is still watching it, but i just pitched a beer(1.050) on top of my slurry from another 1.050 beers secondary. After 3 hours it was going crazy. Did I overpitch my beer? Should I reduce the amount of slurry?

Should I just RDWHAHB?

This topic is covered very thoroughly in the the sticky thread right on this forum:

https://www.homebrewtalk.com/f13/yeast-washing-illustrated-41768/

milldoggy said:

Old post, not sure if anyone is still watching it, but i just pitched a beer(1.050) on top of my slurry from another 1.050 beers secondary. After 3 hours it was going crazy. Did I overpitch my beer? Should I reduce the amount of slurry?

Should I just RDWHAHB?

Click to expand...

You should always Relax and have a homebrew!

Whether you over pitched depends on how much slurry was in your secondary. If you racked the original beer to the secondary when fermentation was finishing up and you didn't get sloppy with your racking you probably slightly over pitched. If you use the entire cake from a primary fermentation you will be over pitching and will probably dumb down the flavor profile of the yeast. The amount that you over pitched will have very little effect IMHO.

Thanks, I used the entire yeast cake from the secondary. It was probably about 2-3 cups. maybe more. So I bet I slightly overpitched. I read the entire yeast washing thread. I did my first wash yesterday and the results look promising. I think I will wash yeast for now on.

Thanks for the response.