Techniques and questions for doing a double mash for ris

[olotti]

so I do a big ris every year from my sons bday then usually bourbon oak age it or use other adjuncts to make it diff every year and this year well I'm 2 months past his bday but whatever so I thought about really making a big ris and borrowing a friends mlt to bump up the og or just to try something diff. So usually I try to hit 11-12% abv so the og is anywhere in the 3 yrs I've done this between 1.112-1.117 but being a big beer efficiency suffers a little but I always end up close. So if I were to do this double mash how exactly do I do this? Do I buy the same amount of grain for each mlt, so it's 23lbs of grain I can hold in my mlt doing a thick mash so would I buy 50 lbs of grain and basically run the same amount of mash in and sparge water through each mlt to collect my wort and hit my pre boil volume. Would I have to boil any longer than the 90 min I usually do now? Any help tips tricks advice would be great and I'd prob do a partygyle if I did this since I'd have a lot of good stuff left in two mlts to make a nice brown ale or even smaller stout. Thanks for reading.

 

[jheinikel]

You essentially divide everything. If you target 6gal to the fermenter, run 2 batches of 3gal to the fermenter. That will ensure the water volumes are correct for mash/sparge and your pre-boil volume should be whatever the original 6gal recipe called for.

 

[olotti]

So I aim for 6 gal final boil vol then 5.5 gal to fermentor. But I guess I'm missing something here do I need 23lbs of grain in each mlt and treat each mlt as it's own beer even though I'm draining all the first runnings into the same kettle and such or are you meaning collect 3 gal from each mlt combine them then boil I can see that as doable also.

 

[jheinikel]

You have it right. Divide the grain bill in half and water volumes in half. Make 2 X 3 gallon beers in each mash tun. Once they are all combined, you end up with the exact grain bill you started with and same pre-boil volume. Just drain all runnings into the same boil kettle.

 

[olotti]

Ok so my goal is to make a bigger ris without adding dme in the boil like I have to now due to mlt capacity. So now instead of using 25lbs of grain or 12.5lbs per mlt I can increase my og by using 2 mlts and increasing the grain bill to say 35lbs or 17lbs per mlt. Ahhh now I see where this is going.