2.5 gallon batches

[ryno1981]

I want to start brewing all grain BIAB 2.5 gallon batches. The reason for the 2.5 gallon batch is because I'm thinking it would be easier to do with the BIAB method. Also, easy to convert 5 gallon recipes. If the batch isn't the best I will end up with 1 case instead of 2. If I brew a batch I like a lot I can easily convert to five gallons and brew again. Anyway, my question is, I only have a 5 gallon carboy and two 6.5 gallon buckets at the moment. Can I ferment 2.5 gallons in the carboy? Or is that too much head space? I'm thinking as long as I leave it in the primary it should be ok, given the CO2. Is that right?


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[dcp27]

yep, that will be fine, I used to do it all the time. good luck!

 

[Foosier]

I will say this. If you want to go all-grain and you think BIAB is the way to get going, and I totally agree that it is, you may want to just go for full 5 gallon batches. The big thing you would want to void is buying a bunch of equipment that works best for 2.5 gallons and then need to get more equipment for 5 gallon batches.

You already have the fermenters, you just need a big pot (10Gallon min works best) and a big bag. From there it is all the same. If you want to do 2.5 gallons anyway, you can, but you won't have to buy more equipment.

Just my $0.02.

FYI. I jumped straight from extract to All grain BIAB and love it.

 

[BigJack]

So long as you don't do secondary fermentations, you are golden. No need to buy anything.

You can buy 3 gallon/12liter better bottles or Spidel fermenters if you want to secondary.

Or you can visit a local bakery and talk them out of a 2.5-3 gallon frosting bucket to use as a secondary.

 

[Flboy]

For buckets, if you live in Georgia/Florida, go to Public's supermarket. The bakery is very active and gladly gives 3 gal and 2 gal buckets--with gasket-ed lids!

 

[ryno1981]

Alright, that's what I needed to hear! Getting started this weekend. Thanks guys!


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[kmind]

Perfect timing. I am also looking into going the BIAB 2.5 gallon direction.

Would a 5 gallon kettle be big enough for most beers?

Sorry to derail the thread...

 

[ryno1981]

I'm planning on doing a five gallon mash. Hopefully ending up with three gallons of wort. Post fermentation I'm guessing I should have about 2.5 gallons.


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[hannibalmdq]

I'm planning on doing a five gallon mash. Hopefully ending up with three gallons of wort. Post fermentation I'm guessing I should have about 2.5 gallons.


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I'm a 2.5 gallon batch brewer. It really depends on your boil off rate and whether you care if you pour trub into your carboy (I don't). My induction top will boil off between .5 and .75 gallons for a 60 and 90 minute boil (about 15% an hour boil off rate). Factor in wort shrinkage and I normally shoot for about 3 gallons post boil to try and get about 2.75 in the fermentor. This means i need either 3.75 or 4 gallons depending on boil length. 5 gallons would be super excessive for my system and lead to a lot of wort not going in the fermentor. But then, it is my system.

YMMV.

 

[hannibalmdq]

It occurs to me you may mean 5 gallons of water pre-mash. Yeah, that would make sense. I'm not a BAIB by depending on the grain bill and whether I'm no-spare or single batch sparging, yeah, 5 gallons is about right.

 

[ryno1981]

It occurs to me you may mean 5 gallons of water pre-mash. Yeah, that would make sense. I'm not a BAIB by depending on the grain bill and whether I'm no-spare or single batch sparging, yeah, 5 gallons is about right.

That's exactly what I meant. I'm glad to know I'm on the right track.


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[ryno1981]

One more question. How hard is it to keep your mash temp. in a kettle with it not being insulated and all? Do you cover and let it rest, or keep checking temp. and adjusting?


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[strambo]

You can cover it and wrap it with a sleeping bag or blankets. I do partial mash BIAB and mash in a smaller 3 gal pot. I heat the oven to low, then turn the oven off and throw my 3 gal pot in there to mash. Only loses about 2 deg in an hour.

I also sometimes do 2.5 gal AG BIAB batches. I typically primary them in a 5 gal better bottle.


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[Munchkin]

So long as you don't do secondary fermentations, you are golden. No need to buy anything.

You can buy 3 gallon/12liter better bottles or Spidel fermenters if you want to secondary.

Or you can visit a local bakery and talk them out of a 2.5-3 gallon frosting bucket to use as a secondary.

the co2 coming out of solution would not be enough to protect the beer in secondary? Im planning on racking a RIS into a carboy with quite abit of headspace and figured itd be ok. I suppose you could co2 purge if you had a keg setup. For those that dont, are you really risking oxidation if your carboy is half full even though the surface area is the same if the carboy was topped up right before the taper of the neck? Is there that much more risk?

 

[dnslater]

I picked up a brewdemon conical for the occasional small batch and it works well. Has a conical base for the yeast grub to settle out and a valve at the bottom. Small and easy for small batches.

 

[wingedcoyote]

the co2 coming out of solution would not be enough to protect the beer in secondary? Im planning on racking a RIS into a carboy with quite abit of headspace and figured itd be ok. I suppose you could co2 purge if you had a keg setup. For those that dont, are you really risking oxidation if your carboy is half full even though the surface area is the same if the carboy was topped up right before the taper of the neck? Is there that much more risk?

The science behind it is not clear to me, but I've had issues with long term use of vessels with lots of headspace (either secondary or month+ primary) and I've seen lots of anecdotes from other people who have as well. It may be that the co2 doesn't act like a solid "blanket" as much as we'd like it to, and instead gradually dissipates and mixes with o2 over time.

 

[peterj]

the co2 coming out of solution would not be enough to protect the beer in secondary? Im planning on racking a RIS into a carboy with quite abit of headspace and figured itd be ok. I suppose you could co2 purge if you had a keg setup. For those that dont, are you really risking oxidation if your carboy is half full even though the surface area is the same if the carboy was topped up right before the taper of the neck? Is there that much more risk?

Yes, aging a beer with a lot of headspace will absolutely lead to oxidation issues. There is not nearly enough CO2 coming out of solution to fill a large amount of headspace. In the primary there is enough CO2 produced to purge virtually all of the other gasses, so headspace is not too big of a deal.

It may be that the co2 doesn't act like a solid "blanket" as much as we'd like it to, and instead gradually dissipates and mixes with o2 over time.

This is exactly it. A lot of people parrot the "CO2 is heavier than oxygen so it will settle out and form a protective blanket" thing, but that is just not how it works. If it really was like that, we would all be dead because all of the CO2 in the atmosphere would settle below the oxygen. The difference in weight between these two molecules is incredibly small. Gasses in a system don't settle out like that. When you put 2 gasses in a closed system they will mix and move around a lot because of a number of different mechanisms. Small disturbances, random vibrations, diffusion, and Brownian motion to name a few.

My point is don't age beer in a vessel with a large amount of headspace. I have my own anecdotal experience with this too, and believe me the results are undesirable.

 

[Munchkin]

Yes, aging a beer with a lot of headspace will absolutely lead to oxidation issues. There is not nearly enough CO2 coming out of solution to fill a large amount of headspace. In the primary there is enough CO2 produced to purge virtually all of the other gasses, so headspace is not too big of a deal.



This is exactly it. A lot of people parrot the "CO2 is heavier than oxygen so it will settle out and form a protective blanket" thing, but that is just not how it works. If it really was like that, we would all be dead because all of the CO2 in the atmosphere would settle below the oxygen. The difference in weight between these two molecules is incredibly small. Gasses in a system don't settle out like that. When you put 2 gasses in a closed system they will mix and move around a lot because of a number of different mechanisms. Small disturbances, random vibrations, diffusion, and Brownian motion to name a few.

My point is don't age beer in a vessel with a large amount of headspace. I have my own anecdotal experience with this too, and believe me the results are undesirable.

Interesting, ill have to do some more research myself since i clearly dont understand the facts behind it.

 

[hoghead_homebrew]

I picked up a brewdemon conical for the occasional small batch and it works well. Has a conical base for the yeast grub to settle out and a valve at the bottom. Small and easy for small batches.

Ive been looking at those brewdemon conicals for about a week now. Did you get the clear or the brown? Any regrets?

 

[RM-MN]

I want to start brewing all grain BIAB 2.5 gallon batches. The reason for the 2.5 gallon batch is because I'm thinking it would be easier to do with the BIAB method. Also, easy to convert 5 gallon recipes. If the batch isn't the best I will end up with 1 case instead of 2. If I brew a batch I like a lot I can easily convert to five gallons and brew again. Anyway, my question is, I only have a 5 gallon carboy and two 6.5 gallon buckets at the moment. Can I ferment 2.5 gallons in the carboy? Or is that too much head space? I'm thinking as long as I leave it in the primary it should be ok, given the CO2. Is that right?


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I brew a lot of 2 1/2 gallon batches and ferment them in my 6 1/2 gallon buckets. The initial fast ferment will fill all that space with CO2. I typically ferment in the bucket for 3 to4 weeks and then bottle.