Double mash for higher gravity

You could do it that way.

But I'd recommend doing two smaller mashes (i.e. 1/2 volume) that each hit the OG you need to get your 12% ABV.

 

The answer is 'yes' to your first question. If you brew two smaller 6% batches and add them to your fermenter you'll just have a 5-gallon, 6% batch.

 

There is also the no sparge method. Efficiency goes out the window but big beers are wasteful.

 

Smaller batches would mean more room for grain on your system.

 

Partial mash. Mash all specialty grain in your recipe plus as much base malt as you can fit in your mash tun without creating problems for yourself. Make up the rest of the required gravity by adding light dme to your boil in the last 15 minutes.

 

Time. You can always make more wort than you need (thus increasing mash efficiency) and boil it down, but at the expense of time.

 

I'll just add that if going this way, DME is the way to do it (vice LME), but personally I wouldn't even go that way. Malt Extract is born stale (i.e. oxidized). It's the reason people have to add it late in the boil to mitigate the color coming out too dark.

 

You could also try "re-iterative mashing." Do your first mash as normal by using tap water, then use the product of that mash as your strike water for another mash. You could do the first mash with all base grain to get a high gravity and no color, then your second mash could be a blend of base grains with all your typical stout specialty grains.

 

He said he could make a 9% beer before maxing out his mash set up. My advice is to use the least amount of extract he can get away with, so roughly 25% of the grist would be extract. I feel pretty confident that if every other effort is made to make a good 12% imperial stout, e.g., proper fermentation controls, water chemistry, and a decent recipe to start with, I would not find it distasteful due to this extract substitution.

If anyone cares to prove me wrong on this feel free to brew a batch with 25% extract as I, and then beermail me.I will provide an address for you to send several bottles of your results so I can provide a more educated opinion.

 

Why not use your exsiting equiptment and mash BIAB, pour off the wort, then add sparge water, slosh the bag around, let it sit for another 10-15 minutes, poor off second wort, then boil?

Seems that would take less time then mashing twice.

Yeah, you'd have to boil longer but a 12 % brew can be made this way.

 

If the weight of the bag is an issue, then hook a come a long to the e ladder. Problem solved.