17 replies to this topic

[McNuggets]

I am cooking up a batch of Southern English Brown, and was thinking that I easily have room in my MLT to mash a 15 gal batch at SEB gravity, but the keggle obviously won't handle that volume. I was thinking that I could mash in for a 10 gallon batch at 1.060, then dilute with 5 gallons of water in my big fermenter to hit 1.040ish. Anybody ever try this?

[Stout_fan]

All the time. I'd have to go look to tell you the exact steps, but Promash allows you to set separate boil and volume sizes. It recalculates hop dilution as well. Just remember your target SRM, OG & IBUs you will be good to go.

Edited by Stout_fan, 02 February 2010 - 06:35 AM.

[Joe]

Excellent idea. By the way, what are you using as a fermentation tank? I have a 15 gallon demijohn, but probably wouldn't put more than 13 gallons in there for primary.

[McNuggets]

I picked up an empty 20 gallon food grade liquid sugar barrel from the LBHS. Not perfect, but does the trick.My only concern is the IBUs. I used beersmith to hit the proper numbers for OG/IBU for a 15 gallon batch. I hope with dilution from 10 gallons, it will be right...

[Patrick C.]

Mine have always come out tasting like I wanted using a simple dilution calculation. If you want 20 IBU in 15 gallons, that's 30 in 10 gallons. Basically you're correct that you want to brew a 1.060 beer and then dump in 5 gallons of water. If you chill the water, it can help cool the wort to pitching temperature. Cool the undiluted wort first to around 80F, then dump in the cold water to get it below 70.The biggest problem for me is controlling the ferment temperature and moving around ~130 pounds of beer and fermenter. I'm guessing that keeping it cool is not a problem in Halifax, but you'll still have to move it around. Can you set it up so you can rack out the beer without lifting the fermenter? I usually rack out 5 gallons, then lift the rest of it out of the fridge to rack the other 10.

[BrewerGeorge]

Works fine. The only hopping complication is that the hops experience higher gravity wort during the boil than they would if you would produce 15 gallons 'normally.' Like Stout_fan says, Promash will handle this for you.If you don't have Promash, set the boil size to 10 gallons (to simulate the boil environment the hops will have) and use enough hops to get 1/3 more IBU's at that setting than you actually want after the dilution.ETA: The above just takes care of raw IBU's. Remember to add 1/3 more flavor and aroma hops as well.

[McNuggets]

PC, I'm cool with not having to move the fermenter. I can actually pressurize it, so it can sit on the floor. It's cool enough up here for sure. brrrrrrGeorge, so if I was aiming for 20 IBU in the finished 15 gallon batch, I should be shooting for 30 in the 10 gallon batch before dilution? No flav/aroma in this beer.

[BrewerGeorge]

....George, so if I was aiming for 20 IBU in the finished 15 gallon batch, I should be shooting for 30 in the 10 gallon batch before dilution? No flav/aroma in this beer.

Yep. IBUs are a measure of concentration and follow the equation: V₁ X B₁ = V₂ X B₂, where V is volume and B is IBUs. In your case it would be 15 gal X 20 IBU = 10 gal X B₂.BTW, a similar equation works to predict gravity at any volume from a known starting gravity and volume. Just replace the B's with G's (gravity in whole numbers ex 1.035 would be entered as just 35.)

[Stout_fan]

And don't forget, you have to cool this thing. 15 gal of brew kicks of a fair amount of heat. Of course, this time of year, the lower temps help.

[Stout_fan]

Right formula George, but extraction is lower in high gravity beers, so it would have to be a bit more than just an equivalent after dilution.

[McNuggets]

Temperature won't be an issue this time of year. The IBU range is 12-20 IIRC, so I have some room to play with. Maybe calculate for 20 IBUs in the finished beer, and let lower hop utilization bring it down into the mid teens. I guess I should boil the dilution water too? I was thinking about doing that, and putting the hot water into a plastic water jug until it was cooled.

[BrewerGeorge]

Right formula George, but extraction is lower in high gravity beers, so it would have to be a bit more than just an equivalent after dilution.

As you and I said, Promash does this automatically if you set the boil volume and final volume to unequal amounts. (That's not the default setting, IIRC. You have to change a setting to allow them to be different.) If you're using another program that doesn't do this, you can trick it by setting the boil volume in your brewing program to 10 gallons. It will then take the higher boil gravity into account when it tells you how much hops to use to get the 30 IBU's.

[McNuggets]

Yup, that will work.

[Stout_fan]

... I guess I should boil the dilution water too? I was thinking about doing that, and putting the hot water into a plastic water jug until it was cooled.

Yes boil the water.Hot water into plastic jug; if too hot it could have plastic go into solution. Also jug must be sanitized.I use a CFWC. So all I do is yank the QDC off the BK and jack it onto the HLT QDC.If you are using an immersion cooler, just do the BK first then the HLT later.

[McNuggets]

Yeah, I was thinking that leaching might be an issue. I'll hit the water jug with SS then put cooler water to it.Edit - I could probably just put the hot water into a sanitized corny...

Edited by McNuggets, 04 February 2010 - 09:04 AM.

[BrewerGeorge]

...Edit - I could probably just put the hot water into a sanitized corny...

I've done that when diluting beers after fermentation when it's important to be as oxygen free as possible. Just make sure you pressurize the cornie with something as it cools - oxygen or sterile air would be best for your pre-ferm but CO2 works if it's all you have- or it will probably break the seal as it contracts and compromise its sterility. Nice thing about the cornie is that you can refrigerate it and use it as part of the wort cooling process.

[Patrick C.]

A 5 gallon polyethylene bucket would be the best thing to dump the water in- safely transfer 5 gallons of boiling water and seal it up and then let it cool. No worries about chemicals like you might have with a PC water bottle, and the hot water will kill any germs. The bucket will collapse a little, but it will spring back when you open it up.

[Stout_fan]

One point about hot wort here.Things like better bottles are blow molded.When you put really hot liquids in it that make it plastic again it will shrink.That's plastic, as in the material state; not the generic reference to the material.