Strategies - too much wort for kettle

I have a 15 gal mash tun and a 20 gal boil kettle. I'm working on a recipe that has a 20.25 gals pre-boil measurement. Even if it was @20 on the dot, it'd be a problem, since I need some space to boil (without boiling over).

So what strategies do you suggest to tackle this. Here's what i thought:
> Buy a bigger pot - yeah right... Maybe if I win the lotto.
> Fill it with 18 gals of wort and drain the additional 2.25 into a bucket and then add it to the boil as the volume drops due to evaporation.
> Top off with water at the end (but how do I adjust BeerSmith to hit my numbers?)

Any other ideas? I think the 2nd option is the way to go on this...

why not just scale back your recipie to say 17gal pre boil?

Beersmith does have a 'scaling' option. In fact i am using it today to scale a usual 5gal recipe to a 3 gallon recipe. Just highlight your recipe, then click the scale icon in the toolbar above and a window will pop open and you can plug in your new batch size and BS takes care of the rest.


You could save the 2+ gallons and add as exaporation occurs. I don't suppose it would much different than adding extract.

If your game, you could reduce the extra 2.25 gallons in another pot down to say 1 gallons and then add it back to the main boil. This is a technique used in Traquair House ale (I'm sure others), to get more depth of flavor. But, your beer will obviously change.

I'm shooting to have ~16 gals post-boil but with my evaporation rate BeerSmith says I need 20.25 pre-boil to get down to that amount... BTW: BeerSmith scaling rules! This is how I learned of the issue - scaling up from 11 gal batch to 16 gal.

Honestly, I think I'm going to just stick with 11gal for a while longer. I just upgraded and I'm working to dial it in there. But the new fermenter looks empty with only 11gals filled in...

you could also do back to back batches. Mash the second while boiling. Thats how real breweries fill those big fermenters. Just a thought. Suppose it depends on how sad that empty looking fermentor makes you.

If you keep some wort out and add it in as things evaporate (boil it in a separate pot) you could then split your hops up in the same ratio and do two boils until you can combine the volumes.

I say this because I'm sure you have a smaller pot around that you could throw on the stove-top and boil whatever wont fit into the large BK...seems very easy, easier than two batches.

Follow up: So, what we ended up doing is to fill the kettle to ~18.5 gallons and then continued to sparge off into a 5 gal bucket for the remaining 2-3 gallons. Then we carefully added the 2-3 gallons of wort to the kettle over the course of the 90 minute boil. This method worked just fine - we didn't even have a boil over and adding the extra wort to the kettle SLOWLY never caused the boil to die off.

The real problem that we encountered on that brew day was that my 15 gallon mash tun wasn't quite big enough for the amount of grain/water needed. We ended up with less SG than planned and had a few spills... But nothing related to the boil kettle.

All in all - we just decided to brew 11 gallon batches and started to plan a complete upgrade of the entire brewery... going to a 20 gal setup next year!

Use 1 less gallon to mash and 2 less gallons to sparge