Pitching on yeast cake always this fast?

I pitched onto a yeast cake last night for the first time. It was a 1.050 Hefe onto a cake of nottingham from a 1.040 Cream Ale. I never did it before because I usually had too much trub in the cake, but this cake was nice and creamy white so I decided to try it out.

I pitched onto it at about 9:00pm, and at 6:30am the krausen had already rose to within a couple inches of the top in a 6.5G carboy (5G batch) and began to drop a little.

Now 5:30pm, the krausen has dropped to about 1/2", and the airlock is still bubbling nicely. So basically within 18-20 hours after pitching, the krausen has risen and fallen, and the most active part of fermentation has passed.

I have never had a fermentation take off so quick, even with a 1L starter. Just curious if this is normal to expect when pitching onto a cake?

KCBrewer said:

Just curious if this is normal to expect when pitching onto a cake?

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I recently pitched a brown on top of a yeast cake and it was going strong within 12 hours. So doesn't seem that unusual to me.

Did it hit 80?

babalu87 said:

Did it hit 80?

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No, it is in a temp controlled fridge at 62*.

Usually, pitching on a yeast cake is considered over pitching, unless you have a really high gravity beer. More yeast per ml of wort will cause a quicker fermentation as the population of yeast will quickly consume the fermentables.

+ 1 on the overpitching. Apparently yeast need to undergo a growth phase in order to provide much of the characteristic flavour they impart to beer. When overpitched they bypass growth and head straight into fermentation.
Use the Mr Malty calculator: http://www.mrmalty.com/calc/calc.html

GT

KCBrewer said:

I have never had a fermentation take off so quick, even with a 1L starter.

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Well, 5 gallons is an order of magnitude larger....

I didn't even think to use Mr. Malty, thanks. I even have that in my favorites. I just read about others pitching directly onto the cakes, so I gave it a shot. And I was happy to be saving myself a carboy cleaning.

According to Mr. Malty, a 1.050 beer only needs 90ml of yeast slurry, or about 3oz. This cake was 1/2" thick across the carboy, so I guess it's a "little" overpitched. And from what I've read, a slower fermenation is better for hefe's to get some ester's.

Oh well, no turning back now! Thanks for the input everyone.

What temperature was the wort when you put it on the yeast cake?

It was 70*

Probably got over 70 before the fridge got it cooled down to 62

Fermentation is exothermic (produces heat)

Think of it this way
Your house fridge (where your food is) is kept around 38.
Put some warm/hot leftovers in there and see how long it takes to cool it down.

Now look at that wort 70 and the fridge set at 62........ takes a LONG time to cool it down to 62 from 70 given that setting of 62.

Fermometers are a great way of knowing just how cool/warm the fermenting beer is.

WB-06 or a liquid yeast like 3068, WLP 300 or 380 are better choices for a Hefeweizen. Nottingham isnt going to lend much in the way of character to the beer

Yeah, that was the only point I was going to make. Hefe wort on Nottingham is more like an American Wheat.

I pitched a Blonde on Hefe yeast cake and it turned out great.
I call it "Blonde Heffer"

If I were you, I wouldn't let it sit on that much yeast/trub for longer than a week or so. From my experience, every time I pitch on a cake, I get off flavors if I let it sit on the cake for longer than a week or so.

Thanks for the info babalu. I plan to do more in the way of temp monitoring/control in the future. I have been doing a little research on the Arduino, which is a pretty handy little circuit board. Once I get it all figured out, and pick some more old fridges to rob parts from, I am planning to build a 6 carboy fermentation chamber that will have either 3 or 6 individually temp controlled chambers with sensors to monitor/control both beer and ambient temps. It is a bit of a project though, so I'm hoping to begin assembly over the winter.

As for the notty yeast, it was all I had. I had pitched all of my other saved yeast after a bout with infection, and have had these extract kits sitting here for while which I hadn't ordered yeast for as I was planning to used the washed yeast that ending up getting dumped. I knew it wasn't ideal, but I was ready to brew.

HalfPint, thanks for the tip. I'll probably go ahead and move it to a secondary next weekend, since it appears it will be at FG by then.

I pitch over a yeast cake every two weeks, never found odd flavors or missing flavors due to overpitching.

In response to the threat's question. It's normal, last week I pitched a 5 gall batch of Imperial Stout over the cake of a Red Ale. 5 hours later it was bubbling like crazy and 3 cm krausen.