Experiences and questions from 20g. batches

Hi all, new to the forum. Just upgraded to a 20 gallon setup with a 30 gallon conical fermenter. I must say, after the cost of the system is forgotten, I really enjoy brewing on the larger setup. I would estimate about a 10% longer brew day, but with the necessary pump to transfer liquid around, the wort chilling with an immersion chiller and the pump recirculating takes down the temp of my batch from boiling to 80F in about 25 min. So far, I have brewed a couple of batches of belgian house and goldens, and a wheat beer.

Now to my question. I have been experiencing very rapid fermentation cycles in my 30g conical fermenter. Typically the yeast begins to flocculate at about 4 days, although the is noticeable smell of CO2. With the 20g batch in my plastic 30g conical, I rarely see bubbles come out of the S type fermentation lock. Even though most yeast has gone from the top of the beer after 4 days, I have been leaving 7-10 days just to make sure fermentation is close to done. The last wheat beer I made was approximately a 5.5% beer, and I pitched with 4 snap packs. The beer seems to have a slight yeasty bite indicating possible over pitching. Everything I read says I should have pitched 7 or more snap packs. The most recent beer, another approximately 5.5% beer (Belgian house) I decided to experiment with 3 snap packs to see if that was the magic number. Again, yeast is off the top of the beer at 4 days, but I can still smell a little bit of CO2 if I uncork the fermentation lock and take a peak. Is there something going on with the bigger batch that makes less pitching better, is it normal to have such quick fermentation, and does the 10 gallon head space have anything to do with it? Thanks so much for your help

Have you been monitoring temp inside the fermenter? Larger batches can get pretty warm from all the extra yeast activity. This could explain why they are completing faster than you're used to.

I'm getting a 20g set up in about 6 weeks, so I am interested in this

+1 on the temps. Do you monitor them or have the vessel cooled somehow?

I don't have any experience with conicals or doing 20g batches. I do brew 10g batches though.

I just wanted to point out that you should probably be doing a starter. For the cost of how many packs of yeast you are using you could probably save more money in the long run by making starters and stepping them up. If you control the starters size you can ensure that you are pitching the correct amount. Check out mrmalty.com.

Pitching too little is probably causing the yeast to stress out and multiply much faster than normal. I'm not an expert but this is just what I would guess...

I do 2L stirplate to 8L intermittent O2 for 16gal batches of ale. Not sure how I'm going to tackle lagers with this setup!

I have not been monitoring the temps, but it's about 78 degrees in my basement in Denver right now, usually stays pretty consistent. Do you monitor you fermenter temp by just sanitizing a instant read thermometer and then sticking it in there from time to time, or is there a cool gadget to get? Hoping to eventually get something more substantial to control temps in the future, any suggestions on something that would fit a 30g conical? What size beaker should I get for 20g batch starters, any recs? Good advice, I think it will save a lot of money in the long run, thanks.

Ideally you want ambient temps to be in the low 60's as the beer will be MUCH warmer than this as active ferm is going on. Building a simple chamber of wood and lining it with insulation board, then setting up a temp controller and means of cooling (window a/c, mini-fridge/fridge coils, etc.) will help tremendously. Putting the yeast on higher temps than they're comfortable can cause off-flavors, which may be the "yeasty" taste you're getting. I also assume you're checking gravity in order to make sure the beer is completely done fermenting, not just waiting X number of days then kegging, right?

I'd say temperature is definitely your problem. If ambient is 78 it could easily be over 90 somewhere inside the fermenter for a batch that size. That will cause the batch to ferment out a lot quiker and result in off flavors. Trying to control ambient temps may not be effective enough. What you need is a cooling coil (similar to an immersion chiller) that goes inside the fermenter. You could either recirculate cold water or glycol though the coil. You will also need to install a thermowell which will not only allow you monitor temps but also run a controller (like a PID) that will operate your circulation pump. There should be more than enough information on the forum to help you with this. I haven't done this myself so I can't really lend anymore advice.