Primary ferment faster in a smaller bucket?

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Oct 1, 2023
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New Jersey
Hi everyone, new to the forum and have been using a lot of the tips included to make my first batch of wine this year, a fig wine sourced from a big fig tree in my yard.

When making it I loaded up a 6.5 gallon primary bucket and realized I had too much material and it would likely overflow once the yeast started fermentation. So instead of having a mess I pitched the yeast and then scooped out about a gallon of material and put it in a smaller 2 gallon bucket.

That was 36 hours ago. Fermentation hasn’t been as fast as I expected but it’s definitely happening. Until today, when I stirred both buckets there was a modest amount of bubbles. However today I noticed that that when I stirred them the smaller bucket is fermenting a lot faster than the larger one. Is this a problem? Should I mix it back in the 6.5 gallon and just let it’s do its thing instead of separating it? My fermentation isn’t that violent so now I don’t think it will overflow too much if it does at all. With all material in the 6.5 gallon bucket I had about an inch of headspace.
Welcome to WMT!

Visible activity does not necessarily means more fermentation. Use a hydrometer to check the SG of each -- if the smaller bucket has a lower SG, then it's fermenting faster.

Change nothing -- the batches are fermenting, leave 'em alone. Don't worry about the rate.

It's very possible the smaller bucket got a larger dose of yeast, which produced a larger colony sooner, so that it is fermenting faster, e.g., more yeast are eating sugar at a higher overall rate.

Don't fill a primary more then 3/4 full -- most of the time it won't matter, but once in a while Mother Nature will mess with you and it will overflow. She has an ugly sense of humor. 🤣

You can purchase purpose-made 7.9 gallon fermenters, and you can also use Rubbermaid Brutes. The Brutes are available from 10 to 44 gallons. If you intend to make small batches, getting a couple of 10 gallon brutes is a good idea. Note -- buy a new Brute, don't re-use one that has already had "stuff" in it. ;)
First, welcome to winemaking talk. Every ferment for me seems to be different, even if they started off the same. I would want more than an inch of headspace at any time, you never know when the yeast might get frisky and overwhelm that. I might mix some of the fastest into the slower, just to help it out some.

You didn't mention if you added any nutrients to your must. That might help some, but it will make that yeast frisky.
Thanks for the replies! Good point I didn’t check the SG yet I’ll do that and see where they’re at.

As for the primary, I accidentally bought a 6.5 gallon bucket when I thought I bought a 10 gallon one (on Amazon) and didn’t realize my mistake until it was too late haha. I’m still hopeful that I can get around five gallons out of it when all is said and done. Next year I’ll definitely switch to a larger bucket though.

I did add nutrients to the must about an hour before I pitched the yeast.

Follow up question…I would like to rack them at the same time, less work, less cleaning etc and I could use the smaller bucket to top off the larger one in the secondary. If the smaller one finishes much earlier can I mix it into the larger one to save myself the trouble of racking it separately?
Welcome to WMT

As Bryan said there isn’t an obvious rate difference based on fermentor size. ,,, warmer will ferment faster and large tends to retain heat, ,,, you could have nutrient differences, ,,, yeast need oxygen for cell reproduction and transferring may oxygenate the must, ,,, more dirt in one which translates to more nitrogen / faster growth, ,,, etc
Some situations as nutrient not mixed would justify mixing
Welcome to WMT!

My 2 cents - my guess is the smaller container will finish first, not because it's fermenting faster but because there's less to ferment.

And have fun with your new hobby!
Thanks everyone for the warm welcome!

For anyone that wants an update, I did check the SG last night. I started the batch around 1.094, the larger bucket was down to 1.090 while the smaller was already at 1.080.

And yeah you definitely can grow figs! You usually need to plant them close to your house and on a south wall for them to last through winter. I finally pruned it last spring and it went crazy afterward growing so much and producing so many figs. I started the wine with 18 pounds of figs because I didn’t feel like waiting anymore, but I probably could’ve gotten about 25 pounds if I waited until they all ripened by the end of November.