Divided Fermentation

Hi Everyone,

After weeks of reading posts here, I finally decided to register and ask some questions directly.

I'm in the process of making a Belgian White at home. This is the first time that I'm using specialty grains, actual hops (as opposed to a hopped extract), liquid yeast, and fermenting in a glass carboy. I decided to take the carboy route for primary because my last batch of mead spoiled in my bucket, and it's been impossible to get rid of the smell of spices and other sour smells. I initially planned to buy a 6.5-gallon carboy, but couldn't find one, so I went with a 6-gallon instead.

After about 20 hours, fermentation was getting out of control, and the yeast was beginning to get into the airlock. So, in a moment of panic, I quickly sanitized the bucket I had lying around, and racked about half of the wort into that. When finished, fermentation continued (and still does) without any problems in both container. After reading horror stories of exploding carboys, I figured I'd take a chance and divide my wort.

I'm planning to do a secondary fermentation of the two together in a 5-gallon carboy next week. Are there any dangers of a spoiled or off-tasting beer if I combine them? Obviously, I'm expecting something off because of the initial problem of not using the bucket. Should I skip secondary and bottle directly from the two separate batches? Is there a danger of too much oxygen in the two containers (they're both about half-way full)?

Thanks,
Bart

Taste the beer in the bucket, and the one in the carboy. If neither one has an offensive odor or flavor, then yea- I would go ahead and combine them.

first of all i really don't think the yeast where getting into your airlock they are not ninjas. if anything the karusen was getting in there, that is common. next time just switch to a blowoff tube.

second using a bucket for primary fermentation is perfectly fine but if your going to do a secondary or extended primary a glass carboy is recommended. plastic is not an oxygen barrier and over time oxygen will seep in from the outside and spoil your brew. during primary fermentation this is not an issue because of all the CO2 that is being pumped out by the yeast. but as soon as thats done oxygen will slowly leak in and oxidize your brew.

now to get to what you where asking about. i am not a fan of using secondaries. its really a matter of preference and is up to you. there will be no harm in doing so just so long as you take steps to avoid oxidizing your brew. as long as fermentation was going when you made the transfer to the second primary the head space in both containers is going to be filled with lots and lots of CO2 which will protect your beer.

TipsyDragon said:

first of all i really don't think the yeast where getting into your airlock they are not ninjas. if anything the karusen was getting in there, that is common. next time just switch to a blowoff tube.
....

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During ale fermentations (top fermenting yeast), the krausen consists of yeast and beer. When the krausen rises enough to hit the airlock- yeast is in the airlock. You should have seen the yeast slurry in the cup that my last blowoff tube was bubbling in!

TipsyDragon said:

first of all i really don't think the yeast where getting into your airlock they are not ninjas. if anything the karusen was getting in there, that is common. next time just switch to a blowoff tube.

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What do you think that krausen is made of?

Thanks for all your quick replies!
I guess those yeast really are ninjas after all...
I'm planning to stick with the glass carboy for primary fermentation in the future because it's neat to see what's going on in there. Instead of adding a blow off tube though I'm planning to add some Fermcap-S to my next batch. Anything I should be aware of before I use it? I read somewhere that it increases bitterness by about 10%. Is that apparent in the final product? Should I just add 10% less bittering hops?

Fermcap-S is awesome, I use it in every batch. I haven't done side by side tests, but I don't think it affects bitterness (nor have I heard that from other people).

That said, do I still need a blow off tube on a 6-gallon carboy when brewing a 5-gallon batch if I use Fermcap-S?

There's obviously a lot of factors (yeast strain, gravity, temps, etc.) but I actually just did a 5 gallon batch with a healthy yeast starter and 8-10 drops of Fermcap-S in a 5 gallon carboy and didn't have any blowoff problems. Here's a picture, after aeration but before pitching:



One thing I do that I think helps is to just leave a piece of aluminum foil over the mouth of the carboy for the first 3 or 4 days of fermentation, then put an airlock on as the really vigorous phase of fermentation starts to die down.

Bartmannj said:

That said, do I still need a blow off tube on a 6-gallon carboy when brewing a 5-gallon batch if I use Fermcap-S?

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Maybe.

Without Fermcap, I've had my 6G carboy with a less vigorous fermentation not reach the neck of the vessel, and a 6.5G carboy pour krausen blowoff through the airlock down the side of the container before I intervened. Both of these were with 5G batches. YMMV :cross:

I've noticed that there are no strict rules. Some people swear by blow off tubes even during secondary fermentation (!). I'm thinking of buying another bung for the carboy, making the hole somewhat larger, and adding a wide long tube leading to a Carlo Rossi gallon jug filled with water. I don't want to mess around with that 90-degree-angle-PVC-pipe setup.
Will this suffice? At least I'll be sure that it's in tight...

I finally got sick of cleaning up the mess in my fermentation freezers, so I just start with a blow-off tube every time now. If I don't need it, I put an airlock on after 36 hours or so. I just use a 1" ID vinyl tube (from local hardware store) that fits the carboy perfectly, and run that into a 1g jug half full of star san. Besides, this way if I end up with closer to 6g in the carboy, it's nothing to worry about.