Use weak wort from 1st batch for 2nd batch?

[devils4ever]

I have a HERMS setup and I'd doing a doubleheader. Since I don't have big enough pots, I'm doing 2 identical batches (Saison) with the same recipe. One for me and one for a friend's party.

Anyhow, I just finished putting the wort into the boil kettle and I have about 2-3 gallons of weak wort left in the mash tun. Can I use that for my second batch instead of pure water? I'll have to add a few gallons of fresh water to make up the needed volume.

I can't think of any reason to not use the weak wort (with water added) for my second batch other than maybe the second batch being stronger.

 

[jerbrew]

The only thing to consider would be your mash pH. Instead of your water coming in at say 8 pH with whatever buffering ability it has your coming in at 5.something with a different amount of alkalinity. I may be getting to the edge of my ability to explain so hopefully someone else can chime in and tell you I'm full of it or expand.

Otherwise this was a common practice to brew really big beers once upon s time.

I can't find that specific article but here's a byo of somebody doing it and they talk a bit on water chemistry.

https://byo.com/bock/item/1317-reiterated-mashing-multiple-mashes-for-massive-brews

 

[devils4ever]

Good point. I never thought about pH. Oh well, the second mash is almost done. I guess it's too late to worry about it. I did add about 50% water to get the proper volume. Time will tell.

 

[devils4ever]

Well, the deal is done. I didn't see any differences with the second mash other than higher efficiency (as expected). I'll see if there are any taste differences in a few weeks when I keg these bad boys!

 

[madscientist451]

I use extra runnings from time to time, I just put it a smaller pot and boil it down. I do check the gravity first, its usually in the 1.020-1.030 range. Its a good opportunity to experiment or use up small quantities of hops I have around. I'll add some LME, usually rye or a dark LME about 10 min. from the end of the boil to bring the ABV up, and maybe add a little sugar. I just wing it and go with what I have available. Sometimes my thrown together "second beer" comes out just as good or better than the first beer . I usually shoot for 2-2.5 gallons for the second beer and use a 3 gallon carboy for fermenting.
I'd guess on average, 4 out of 5 times I get a decent beer doing this, but now and then I don't like it and pour it out.