Effective Volume vs. Total Volume

[BrewDrum]

I'm getting some quotes for a 15bbl MLT/BK/W, and I have a bit of an elementary question for volume. My goal is to have 15bbl, and be able to fill the 15bbl FV (obviously with room for headspace). Most beers are 6-7% and a few up to 9-10%. I'm worried about my mash tun holding the capacity for the higher grains, or if I'll need to double-batch.

One quote shows: 15BBL MLT to be EV=13.5BBL, and TV=23BBL. BK - EV=16.3BBL and TV=26BBL

Should I be sizing the MLT to be 17-20BBL, to single brew?

[gitchegumee]

Need to know more...

Do you have rakes? What is your desired liquor/grain ratio for mashing? Is your thickest mash 100% barley malt? You would normally size your mash tun to hold 110% of your largest mash below the rakes. PM me if you need help with this. Good luck!

[BrewDrum]

I'm going to PM you. Thank you!

[CopperKettle]

If the manufacturer can't answer these questions easily and quickly you are buying from the wrong people!

Typically it will be difficult to efficiently brew both 4-6% ABV mashes and 10%+ ABV mashes at full batch size from the same mash tun. You either have to sacrifice having a really shallow grain bed on your low ABV beers or a really deep mash bed on high ABV beers. You can't have it both ways. I would plan on using malt extract for 10-20% of your fermentables on really big beers unless the vast majority of your production will be high ABV.

[BrewDrum]

They're answering my questions. I guess I feel more comfort hearing different views on this. My biggest beer is 10%, and plan on an English Barleywine...but there's no way that's going to be a single batch.

What you're saying makes sense, or I'll just double batch that one particular beer. Good feedback!

[Natrat]

I have found that most off-the-shelf brewery designs have undersized mash tuns. Often, in order to get enough grain in for really big beers, the grain bed gets too deep and heavy, which leads to lauter and sparge problems...which lead to waaaay lower efficiencies. Rakes definitely change the equation, but if you're going to be doing beers >7.5% on a regular basis, I'd look at increasing the diameter of a given mash tun...which reduces your bed depth.