I'm trying to plan on brewing two single hopped apa's using the same grain bill to see how the hops play separately. I wanted to do one mash, two separate boils with the collected wort and ferment in two vessels. The problem is I only have a 5 gallon carboy and a 6.5 gallon bucket for fermentation. So my question is will only 2.5 gallons in each vessel leave too much headspace?
"So my question is will only 2.5 gallons in each vessel leave too much headspace?" Not for a primary fermentation. You should not conduct a secondary with that amount of headspace. Cheers!
probably not during primary fermentation, but it might, that's more headspace than wort... generally shoot for 20% or so. if you can, you'd be much better off scaling your mash up to 8-10 gallons total, since you're splitting the batch for the boil you only need that much volume in your mash tun. once you're at 8-10 gallons, i'd also recommend a yeast starter instead of direct pitch, and really good oxygenation (might be time to get an oxygen stone if you don't already have one), these will both get your fermentation off the ground much more quickly, and (hopefully) finished faster. this will mitigate the issue of too much headspace. check gravity within a couple days after lively fermentation dies down and once you reach terminal, bottle/keg it as quickly as possible.
Thanks for the information, I appreciate it. It looks like I'll be doing two separate 5 gallon batches to accomplish my goal, I don't have the kettle capacity to do two simultaneous 4 gallon batches right now. And I also don't have enough equipment to mash more than 9 lbs of grain, I'm still doing partial extract brews for now too. Which is okay because for middle of the road abv 5-7%, I'm able to do 50% or less extract. Oh well, I'll have to try and do this experiment again when I have more capacity.
I don't think a secondary would be necessary, I've had success dry-hopping right in the primary so far. My only headspace concern is oxidation.
as long as you're using the same malt bill and yeast strain, and you've got your process down pretty well, i'd say the experiment is still pretty valid. i've actually got the materials at home to do the same experiment but i went with 4 different hop strains across 4 batches... it's a good thing i really like APA!
That is not much of a worry during the primary fermentation since the CO2 produced will 'scrub out' the air (oxygen) in the headspace. I primary ferment in a 7.9 gallon plastic bucket and I have fermented several 3 gallon batches in that bucket; The 4.9 gallons of headspace in my bucket has never resulted in oxidation in my beers. Cheers!
Well with that in mind maybe I can still pull it off and try this small double brew. I haven't been brewing long and I'm really trying to do a few single hop batches so I can get a real feel for how the hop flavors work in different brews. Thanks for the info, I can always count on ba homebrewers to help out. Cheers!
Yeah I'd hope so, then all those fresh delicious apa's don't get old. I've got my girlfriend, a certified hop head, and some of my friends to help me take down all the brews I make. Cheers!
