Noobie Question. Yeast Cake

What is pitching to a cake mean exactly. Is it beneficial? Can you post procedures. Thanks

When you have a batch of beer that is done fermenting you rack (transfer) the beer to another vessel. The gunk left in the bottom of the fermentor is the "yeast cake". It contains many times the amount of yeast you originally pitched in the wort. Using the entire yeast cake for a normal strength beer may be a bit overkill but for some big ones (barley wines, belgians) it may be worth it. The advantage to using the cake is that there is a metric butt-ton of yeast to get to work on your wort. Your batch will start fermenting faster and will finish sooner.

Some good info here:
https://www.homebrewtalk.com/f39/yeast-starters-yeast-cakes-91073/

So let me ask this.
I transfer the IPA into the secondary, brew up my Scotch ale that may have an OG of around 1.070. How long can the cake wait for the wort to arrive, what about wort temps, infection? Do I stir it up? Is there a thread or detailed instructions some where to do this?

I'd love to get some specific details on this as well.

me too!

If the beer that was in the primary you just transferred to secondary or keg tasted good I would re use the cake in the primary right away. If you keep some beer over the yeast it will be good for a week if kept at fermentation temperature. Just add your next wort to this yeast still in the primary and aerate. It should take right off. Do not try to re-use yeast from a high gravity brew as the yeast are stressed and may not perform well. Be very sanitary and you will have no problem.

Okay, let me preface this reply by saying I do not advocate or approve of this method. It's dirty (because it puts fresh wort into a dirty fermenter), it's improper pitching (because except in the most extreme of circumstances, it's waaaaay too much yeast, even for big beers); it just isn't good practice. That's an opinion backed by experience and an overwhelming amount of brewing science. But others' opinions differ.

The technique is to time the racking to coincide with a brew. Thus, while your wort is boiling or chilling - depending on your brewery's procedure - you rack fermented beer from the primary to another vessel. The idea is to allow as little time as possible to tick by between the end of the rack and knockout from the kettle. It's easy!

Give it a try if you must. I'd prefer to see anyone considering this method become a better brewer by harvesting and pitching the correct amount of slurry rather than succumb to laziness.

Bob

I'm doing this myself today, but I don't like to pitch on the whole cake. I have a 1.070 stout that will go onto a Nottingham cake from a Pale Ale that's going into secondary about 2 hours prior, and I'll remove a lot of the cake and use only about 1/3 of it for the new brew.

I don't go out of my way to reuse yeast (I use mostly dry anyway) and usually only do it if the timing and the styles of the brews work out that way. Nevertheless it's a technique and it doesn't hurt to know how to do it properly.

NQ3X said:

Okay, let me preface this reply by saying I do not advocate or approve of this method. It's dirty (because it puts fresh wort into a dirty fermenter), it's improper pitching (because except in the most extreme of circumstances, it's waaaaay too much yeast, even for big beers); it just isn't good practice. That's an opinion backed by experience and an overwhelming amount of brewing science. But others' opinions differ.

Click to expand...

While all of the above is true it can be done with good results. You are taking a chance but to each his own. I personally have always had good results but only use yeast cakes from liquid yeast to brew a second batch and do not experience problems because I use very good sanitary practices and ferment in a temperature controlled freezer which may contribute to the success I have when reusing a yeast cake. Although the fermenter looks messy with trub and hops it is quite sanitary inside (It has to be in order that the beer taste good). Your mileage may very.

i have heard about this overpitching of yeast when recycling a yeast cake quite alot.

my question, comment how can you be overpitching? why is it too much yeast?

if you start with 10 billion yeast in your starter, and your finished cake has 200 billion viable yeast in which your pitching on, then one could summize the last batch actually required this 200 billion, and the next batch wont be underpitched like the first one was!
seems all that reproducing slows the process to my feeble mind.

numbers were just pulled out of my arse, i know 10b is too much as well
and, fwiw, i have never done this. i do not rack on brew day.

nosmatt said:

my question, comment how can you be overpitching? why is it too much yeast?

if you start with 10 billion yeast in your starter, and your finished cake has 200 billion viable yeast in which your pitching on, then one could summize the last batch actually required this 200 billion, and the next batch wont be underpitched like the first one was!
seems all that reproducing slows the process to my feeble mind.

numbers were just pulled out of my arse, i know 10b is too much as well

Click to expand...

You could inoculate with the amount of yeast needed for full cellular saturation in the wort. This eliminates the reproductive or aerobic phase of the yeast colony's life cycle.

The rule of thumb for proper pitching is one million cells per degree Plato per milliliter of wort. George Fix, in An Analysis of Brewing Techniques, specifies 1.5 million for a lager and 0.75 million for an ale.

Pitching too much yeast reduces or eliminates ester formation, because esters are formed during the aerobic phase. During its aerobic production, yeast accumulates unsaturated fatty acids and sterols to produce biomass in the first stage of fermentation. That's when esters are formed - and esters are crucial to ale flavor profiles.

Excessive cellular matter and biomass can lead to early autolysis and "yeast bite".

As WBC wrote, it is possible to knock out onto a cake and make decent beer. Brewers do it all the time. With proper oxygenation and sanitation, the wort will ferment. But it's still not the best practice, not by a long shot.

Look, you don't have to believe me. Believe JZ when he says, "I know a number of people dump a new batch on top of the yeast cake, but you're not going to get the best beer that way."

'Nuff said!

Bob

thanks bob. i have not yet seen it described that way!

ok, makes more sense now to my feeble mind. like i said, i do not practice this, as brew day is BREW day, not bottling day. i do not secondary...and the yeast i use (us05, us04, and nottingham) are all so damned cheap i see no reason at this point to risk a bad batch over two dollars.

NQ3X that avatar rocks!! Brings me back many years, back when Gary Gygax was still alive.

Gawd rest thee, Gary, and may flights of aasimon sing thee to thy rest.

Glad you like the avatar, Red. Feel free to pinch it for your own use. I did; nicked it from a LiveJournal acquaintance.

Bob