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Author Topic: Adequate headspace?  (Read 130 times)

Offline nvshooter2276

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Adequate headspace?
« on: June 22, 2024, 05:09:59 pm »
I have a bucket that's eleven inches deep. The 2.92 gallons I wish to ferment in the bucket will come up to eight inches of that eleven-inch depth. 8 divided by 11 is 0.723, leaving a headspace of 27.3% of the volume I want to ferment. Would that be enough? My plan is to ferment two of the 1.87-pound mr. beer tins (3.74 pounds) in the total fermented volume (TFV) of 2.92 gallons. 3.74 divided by 2.92 is 1.28 pounds of malt per fermented gallon. My "somewhat flexible" standard for a beer with enough malt in it is 1.25 pounds per gallon, so 1.28 is fine. Would the nearly thirty percent headspace be enough? If not I have the tall, 6.5-gallon buckets. I just want to use the eleven-inch one for grits and shiggles...


Another question to ask without starting a new topic: Is it possible to use a transfer valve as a blow-off tube? Without going into an explanation that would put Tolstoy's "War and Peace" into the Short Story category, I need to use a transfer valve with a one-inch ID machine bearing under it, said bearing to be hard against a neoprene fender washer with a one-inch hole in it. A 3/4" NPT thread is a tiny bit too big for a nylon washer, but the machine bearing goes right over the one-inch thread on the transfer valve. I have a rat-tail file somewhere around here but can't find it right now to file-away a little bit of the nylon so I can use that instead of the zinc-plated machine bearing. I want something that won't rust during the three-week fermentation period.

Does PVC tubing with a criss-cross weave in it bend and kink too much? I know the stuff without a braid in it does, and quite easily. Must avoid pinching-off the exit for the carbon dioxide gas created during fermentaion...
« Last Edit: June 22, 2024, 06:39:35 pm by nvshooter2276 »

Offline Drewch

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Re: Adequate headspace?
« Reply #1 on: June 22, 2024, 07:49:48 pm »
27% ullage should be plenty. I routinely do 5-liter batches in 2-gallon (7.5- liter) buckets and have never come close to a blowout.

1 - (5 ÷ 7.57) ≈ 30% ullage.
The Other Drew

Home fermentations since 2019.

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Offline nvshooter2276

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Re: Adequate headspace?
« Reply #2 on: June 22, 2024, 08:01:30 pm »
. . .leaving a headspace of 27.3% of the volume I want to ferment. Would that be enough? My plan is to ferment two of the 1.87-pound mr. beer tins (3.74 pounds) in the total fermented volume (TFV) of 2.92 gallons. 3.74 divided by 2.92 is 1.28 pounds of malt per fermented gallon. My "somewhat flexible" standard for a beer with enough malt in it is 1.25 pounds per gallon, so 1.28 is fine.
Dividing 3.74 pounds of malt syrup into 3.0 total gallons (easier to measure than 2.92 gallons) to be fermented gives us a dilution of 1.2467 pounds per gallon-- close enough to 1.25 lbs./gallon for government work. I'll just go ahead and use a 6.5-gallon bucket and fear not for an overly-vigorous fermentation. mr. beer's dilution of the 1.87-pound cans is 0.88 pounds per gallon, so mine will be 41.67% heavier on the malt side. My most sincere apologies for so wantonly consuming your time...

Offline nvshooter2276

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Re: Adequate headspace?
« Reply #3 on: June 22, 2024, 08:11:10 pm »
27% ullage should be plenty. I routinely do 5-liter batches in 2-gallon (7.5- liter) buckets and have never come close to a blowout.

1 - (5 ÷ 7.57) ≈ 30% ullage.
33.95%, so you're very deep into the green zone...