Boil volume needed for first 10 gallon batch

I'm getting ready to brew my first 10 gallon batch on Saturday. I'm making a maple syrup/mollasses marzen and ale. The first fermentor gets Irish ale yeast, the second fermentor gets Marzen lager yeast, thus 2 "different" kinds of beer.

I was planning on making it an 11 gallon batch, so each fermentor would get about 5.5 gallons to account for losses. The problem is BeerSmith is calculating I'll have an estimated pre-boil volume of 14.48 gallons...which only leaves 1 gallon of extra space in my stainless keggle. What should I do? That seems like an awful lot of pre-boil volume. I know I'm not going to boil off 3.5 gallons...I'm not even sure how it is coming up with these numbers. Any thoughts?

I don't use beersmith but from what I've read part of setting up your profile is giving a boil off percentage. Check your settings. I'm pretty sure BS uses a percentage rather than a fixed amount The fact that BS uses percentage is quite frustrating to many HBTers. You could do a couple things before brew day.

1. Fill your brew pot with 10 gallons is water and boil it for 60 minutes. Take note of how many gallons are left. If you have 8.5 gallons left then you can plan on boiling off 1.5 gallons with a 60 minute boil. So if you want 11 gallons going into the fermenter factor (11 gallons + volume lost to trub + boiloff volume) = total preboil wort volume. This is always good to do to gat your system dialed in.

2. Skip the test boil and just figure you'll lose about 1.5 gallons during the boil. Take a guess of the losses to trub and just go with it. Keep track this time and factor that in to the next brew day.

Are you sure your boil time is correct? My last 90 minute boil, I started with 14.4 gallons in my keggle. I have boil off set at 9%/hour and it seems to work out for me. Fermcap is good stuff when you are reaching the limits.

I do 14.5 preboils all the time. Just watch the heat on hot break and first hop addition foam and you be fine.

I agree with hafmpty mostly.

But you don't have to bring 10Gs to a boil and measure, it waste propane. As you mentioned, boil off is not a percentage it is an amount per hour and dependent mainly on the vigor of the boil and surface area of the kettle. The vigor isn't always easy to control but unless you change brew pots the surface area is the same. Boil a couple gallons for an hour see how much boils off. That will give you a good idea of boil off. Do this a few times, take notes and come up with your average given your normal boil.. Vigorous, not so vigorous, gentle boil.. etc

You can easily measure mash tun loss by putting water in it and draining into your brew kettle exactly as if you were doing on brew day. Don't leave hoses off. Whatever liquid is left is pretty much what will be left on brew day.

Trub in the brew kettle.. I try to to empty the kettle, trub and all. Trub will settle out during fermentation and I want as much liquid out of it as I can get. But at least put some water in your BK a few times and drain to your fermenter bucket/carboy, again just like on brewday. See how much water is left. If you are using a carboy to test this out please don't let boiling hot water or wort drain directly into it. Hot water cool glass could shatter a glass carboy or weaken it.

Hope I helped.

Thanks everyone!

I have my boil time set to 90 minutes and in my previous experiences I lose about 10% an hour, give or take. So I figure I'll lose about 2 gallons and get it down to 12.5 or so, and then leave 1.5 gallons or so in the kettle for trub loss so I guess that would work out.

I don't have any fermcap so I guess I'll need to take it real easy around the start of the boil and then when I add the first hop additions...that makes me nervous only having 1 gallon of headspace...

ziggy13 said:

...in my previous experiences I lose about 10% an hour, give or take.

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Not to be a PITA ziggy13, but I would recommend that you stop thinking of boil off in percentage terms. Think of it in gallons per hour or liters per hour. The percentage idea breaks down if you adjust your volumes. For a 10-gal batch that starts at 12.5-gal like you're doing, 10% is 1.25-gal which would get you in the right volume ballpark for what you're doing.

But what if you're doing a smaller 5-gal batch that starts at 6.5-gal? You won't boil off .65-gal. You'll still boil off at the same rate you would a 10-gal batch. It's not a percentage, it's a specific volume.

I'm not like Dan. I don't get all the sludge and trub into my fermenter. I know it'll settle out, but I don't want hot and cold break in my fermenter. That's why I figure out my trub volume. I don't know what your keggle's diptube looks like, but I would recommend that you keep track over the next couple brews how much is actually left in the keggle after your rack to your fermenter. This will allow you to really dial in your volumes.

I whole-heartedly agree with Dan though about boiling water for an hour see how much boils off. I do full volume tests for my own system because propane is cheap (for me) and I also want to factor in the evaporation that takes place while the water is heating up. Boiling 2 or 3 gallons will give you boil off amount, but boiling 10 gallons will give you boil off amount AND what you can expect to lose in steam and evaporation over the 30-40 minutes that the water is heating up to boil.

Whatever you do though, take Dan's advice and boil some volume of water and do it a few times and take notes. That will give you a good idea of boil off.

Also, I don't know what you're keggle design is, but 1.5gal of trub seems high. Maybe that's what your system leaves in the bottom. Take a measurement after you transfer the wort to the fermenter. That way you will be that much closer to having your number pretty well dialed in.

I've just recently started taking extensive notes every brew session on this stuff. I do it first because I like to. But second, it helps in diagnosing problems and creating, adapting, and adjusting recipes to come out correctly on YOUR system.

Just a few suggestions. FWIW.

Not a PITA at all hafmpty, thanks for the suggestions. I need to do some testing tonight to apply stickers to my sight gauges for volume, and to heat test the o-rings and seals, so that sounds like a great time to track and record my approximate boil off rate.

Previously I did not have a dip tube in my keggle, but I recently purchased the bent copper piece that MoreBeer sells as a boil kettle tube. I bet with that thing I'll leave around .5 gallons in the kettle.

Have fun tonight! I don't know about you, but I enjoy the "process" side of brewing as much as the actual brewing (and the beer drinking).

Personally, I'd just set my target to 11.0 gallons pre-boil, and adjust the final volume with water if needed (prior to chilling).

Take notes, and the next time you will know how much more or less volume to have at pre-boil.

My system boils off 2.5 gal/hr. It's a lot, but it is what it is.

MC

Well the default settings in Beersmith were WAY off. My system boils off about 1 gallon per hour, so I'm really glad I did a test first. Beersmith had me needing 14.48 gallons to get down to 11 gallons into my fermentors in a 90 minute boil. That's more than double what my system does. Well worth the propane.

ziggy13 said:

Well the default settings in Beersmith were WAY off. My system boils off about 1 gallon per hour, so I'm really glad I did a test first. Beersmith had me needing 14.48 gallons to get down to 11 gallons into my fermentors in a 90 minute boil. That's more than double what my system does. Well worth the propane.

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That is real data and probably exactly what you needed. We can tell you all day long how our systems work but it really means nothing. Trial and error is best!