Secondary yeast cakes, big beers and a hello

Yeast & Fermentation
1

Hi Northern Brewer,
First time poster here.

Our group has significantly upped our rate of brewing. I’ve read about pitching beer on top of yeast cakes, and that often it is over-pitching and will lead to yeast-bite or over-attenuation (are those the same thing). It is recommended that you remove the yeast and then use the 1/3 of the yeast cake.

I had a few questions:

  1. How do you physically do this and maintain sanitation? Should I sanitize the top of the fermenter and pour it out into a clean flask, the wash the fermenter, and put the yeast back in?

  2. It is okay to use the entire yeast cake for big beers, like an imperial stout or a barleywine? Are there rough guidelines for what OG would be best for using the whole yeast cake?

  3. Can I use a yeast cake, if there is one, from a secondary fermentation? I know that it is often smaller, obviously, but is there any way to judge that its enough or too much by volume.

  4. Can I use a yeast cake to pitch a cider onto. Has anyone ever done this and what are their results?

2

Welcome!

1 - Sanitize a ladle and just scoop it out.

2 - That’s how it’s done unless you want to spend a fortune. Usually you ferment a small beer, rack it off and pour a big beer on top of that.

3 - I don’t see why not. Should be enough yeast there for a beer… not a barleywine, but a normal beer for sure. The yeast that settle out in secondary tend to have lower flocculation though.

4 - Probably, though I have no experience with ciders.

3

  1. Boil two qts water for 15 minutes, then chill to fridge temp. Sanitize three one-qt Ball jars and lids. Rack the beer off the cake, then add one quart of the cold water to the fermenter and swirl to loosen the cake. Set up your jars and divide the yeast between the jars, then top off with more cold water if there’s room. Store in the fridge until needed.

  2. My general ROT for reusing the yeast is one jar for up to 1.060 and two jars for anything bigger. You could use the whole cake, but it’s probably over-pitching, plus it’s nice to have that third jar for making a new batch of smaller beer (and repeating the harvesting routine, too).

  3. I wouldn’t use the yeast from the secondary because one, it’s going to be less flocculant in the next generation (as already mentioned) and two, it’s been through a longer period sitting in a low-pH and high-ABV environment so it’s not as healthy as what you get from the primary (or even better, from top-cropping).

  4. You can certainly pitch a cider on a cake, but you’ll want to watch the color and character contributions from the previous beer or do at least one rinse of the yeast to clean it up. You’ll also want to watch the fermentation temp as the yeast will go nuts on the simple sugar in the cider.

4

Another quick question: What if the yeast cake is a beer that had spices added to it (e.g. a spiced pumpkin ale)? Is washing enough to remove those flavors?

5

One rinse will remove most of the previous beer character, two will take it down to levels that won’t impact a following brew.

6

Haha!
I once put a wheat beer on top of a pumpkin ale cake and I got a pumpkin spice wheat ale… Very much so… People actually liked it though…