Jurassic yeast cake

[Sadu]

Hey everyone,

What's a normal sized trub / yeast cake layer for an AG batch?

My first 2 brews were kit and kilo, about an inch or so of cake and trub at the bottom out of 23 litres, seemed like not much.

Next brew was an all-grain NZ Pale Ale with US-05 OG 1.054, I racked to secondary after 6 days because primary fermentation was winding up (best time to rack it according to How to brew) and I needed the bigger fermenter. At this point I noticed the yeast cake was pretty big, sitting well over the spigot. I started with 24 litres in primary and ended with 21 litres in secondary.

Next batch (all grain Blonde Ale, also US-05) I decided to pitch onto the cake directly, I'm cheap and I need to keep costs down. I removed 5 cups of cake (about half), pitched straight on top. Fermentation took off like a batmobile and went from 1.048 to 1.007 in 4 days. I get that I overpitched, meh won't happen again and I learned a new skill and gained confidence. I harvested and washed the krausen for next time.

The cake on the blonde ale is almost 5.5 litres out of 24. A good chunk of that will be from the previous batch, but still seems like a lot.

Is it normal for the cake to compact down from here or am I stuck with 18 or so litres of beer instead of 24?

For what it's worth, the hydrometer samples on both taste amazing.

Edit: fermenting at 18c / 65f for both of these. Temperatures have been quite constant.

 

[RM-MN]

Like many things in books, the instructions that you need to rack to secondary before a week is over is outdated. With the yeasts we have available now there isn't any rush to rack to secondary and many of us have quit using secondary with few exceptions because we've found that leaving the beer on the trub is beneficial and racking to secondary has risks of its own including infection. If you leave the beer in the primary longer the trub will compact down, releasing the beer trapped in it. That means you get more beer into the bottles instead of dumping it out with the trub.

Yes you over pitched with using 1/2 half of the yeast cake. The normal suggested amount is about 1/4. Over pitching isn't really bad at the amount you did. Here's the results of an experiment done that compares under pitching and over pitching with a normal pitch. Note the amount of over pitch and under pitch and the results of each. Your over pitch wasn't out of line.
https://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

 

[Hillman]

interestingly racking to secondary has been in and out of fashion a few times in the last few decades. Yep, you pitched that brew pretty hard but it is not a major factor. Washing yeast is also loved and hated. Nothing wrong with a straight re pitch, but I would tend to take out half a cup, clean the fermenter and pitch the half cup back in to the new brew

 

[Sadu]

Yep, I have done a fair bit of reading and everyone has their own opinion on secondary, which is cool. No doubt I'll develop my own opinion on that in due course.

The main thing for me is that one fermenter has a temperature probe inside the beer with a digital readout and status LEDs. The other one has an old stick-on which doesn't work that well, and it's not my fermenter so I can't go drilling holes for probes in the lid.
So for this reason I figure it's worth shifting the previous brew to secondary so I can keep tight temperature control over the new brew during the main fermentation. If the beer comes out a bit clearer as a result, or not, that's fine too.

The overpitching was a mistake, being a beginner I wanted to err on the side of overpitching rather than underpitching. Now I have seen the results of doing this I can do so with more confidence next time.

 

[RM-MN]

Yep, I have done a fair bit of reading and everyone has their own opinion on secondary, which is cool. No doubt I'll develop my own opinion on that in due course.

The main thing for me is that one fermenter has a temperature probe inside the beer with a digital readout and status LEDs. The other one has an old stick-on which doesn't work that well, and it's not my fermenter so I can't go drilling holes for probes in the lid.
So for this reason I figure it's worth shifting the previous brew to secondary so I can keep tight temperature control over the new brew during the main fermentation. If the beer comes out a bit clearer as a result, or not, that's fine too.

The overpitching was a mistake, being a beginner I wanted to err on the side of overpitching rather than underpitching. Now I have seen the results of doing this I can do so with more confidence next time.

Temperature control is necessary for good beer. Tight temperature control isn't very necessary. I try to keep mine within a 5 degree range.

For what it is worth, experiments with thermowells and stick on thermometers show that there may be a half degree difference between the thermowell and the exterior of the fermenter. That has little significance in brewing beer.