Conversion to partial mash

loctones · 09-04-2009, 03:30 AM

I'm planning an imperial stout, but the amount of grain required is too much to fit in my MLT. I can only fit about 12 lbs. So, I'm trying to convert it to martial mash. I'm using BeerSmith, and the Convert utility doesn't seem to allow me to specify how much grain I want to use.

As a work around, I did the following: I set up everything as I would an all-grain batch. Then, I manually calculated how much grain over 12 lbs. I had. To calculate the amount of extract I need, I made a separate recipe in BeerSmith containing only the amount of 2 row I needed over my maximum of 12 lbs. I then converted the 2 row only recipe to extract, and used that information to build my finished partial mash recipe.

I don't see any problems with this approach, but I've not done this before. Is this a valid way to do the conversion?

LordHedgie · 09-04-2009, 04:10 AM

Yeah, I suppose so. I hate to admit it as a hardcore Linux hacker, but I don't like to rely on computer programs to build my recipes. Your approach should work fine. I think you'd also get fine results by taking all the 2-row over the 12 lb grain bill, multiplying that by 0.75, and using that much LME in the boil. YMMV.

homebrewer_99 · 09-04-2009, 04:32 AM

How about a recipe to read? Without that there are way too many variables to choose from that may/may not get you the reply you're looking for.

VTBrewer · 09-04-2009, 04:36 AM

your conversion is correct. and from a linux guy, just use brewblogger.net ton of us on here use it.

loctones · 09-04-2009, 05:23 AM

Here's the recipe I ended up with. I started of with Jamil Zainasheff's RIS recipe (Jamil's Brewing Network Program Recipes), scaled it to 5.5 gal, and changed it for my efficiency.

Amount Item Type % or IBU
5.79 lb Pale Liquid Extract [Boil for 15 min] Extract 33.28 %
8.00 lb Pale Malt (2 Row) UK (3.0 SRM) Grain 45.98 %
1.20 lb Roasted Barley (300.0 SRM) Grain 6.91 %
0.80 lb Chocolate Malt - Light (200-250 L) (337.0 SRM) Grain 4.61 %
0.80 lb Special B Malt (180.0 SRM) Grain 4.61 %
0.40 lb Caramunich Malt (56.0 SRM) Grain 2.30 %
0.40 lb Chocolate Malt (350.0 SRM) Grain 2.30 %
1.25 oz Magnum [15.00 %] (60 min) Hops 44.8 IBU
1.93 oz Goldings, East Kent [5.90 %] (10 min) Hops 9.8 IBU
1.93 oz Goldings, East Kent [5.00 %] (1 min) Hops 1.0 IBU
1 Pkgs California Ale (White Labs #WLP001) Yeast-Ale

The LME is a conversion of the extra 7.15 lb of Pale Malt that wouldn't fit in my MLT. It looks like the 0.75 conversion factor given by LordHedgie is pretty close for me.

VTBrewer, thanks for the tip on BrewBlogger. It looks pretty cool, and I always appreciate open source code. I'll install it on my server and play around with it. I've been wanting a common way to view recipes on both my desktop and my laptop. This might work great for me.

homebrewer_99 · 09-04-2009, 12:40 PM

I usually tend to keep all the specialty malts and convert the largest malt.

I'm assuming you'll add the LME at flame out so your specialty malt is under 3 lbs. leaving 8 pale.

Wait...8+3 are 11. You sure you can't fit all the grains in?

1 lb of grain equals .75 lb LME and/or .6 lb DME.

If you use 5 lbs of grain that leaves 3 lbs you'll need to convert to DME or 1.8 lbs.

So you could use 5 lbs Pale and 3 of the specialty malts plus 1.8 lbs DME added with your 5.79 lbs of LME.

Does that work for you?

**Bobby_M** · 09-04-2009, 01:31 PM

You could have just reduced the amount of base malt to the max you could use in the tun and add extract until the OG was back to the recipe's spec.

loctones · 09-04-2009, 04:32 PM

Thanks, homebrewer_99. The recipe I posted was after the conversion. There's definitely no way I could have fit 17 lbs of grain into my MLT. The .75 for LME and .6 for DME is the conversion I implicitly made with my software.

Bobby_M, that's a good suggestion. I will try that and see if I come up with the same thing. It certainly seems a lot simpler than what I did originally.

Time to brew it up tomorrow!

homebrewer_99 · 09-04-2009, 04:46 PM

Quote:

Originally Posted by loctones

Thanks, homebrewer_99. The recipe I posted was after the conversion. There's definitely no way I could have fit 17 lbs of grain into my MLT. The .75 for LME and .6 for DME is the conversion I implicitly made with my software.

Bobby_M, that's a good suggestion. I will try that and see if I come up with the same thing. It certainly seems a lot simpler than what I did originally.

Time to brew it up tomorrow!

OK, I stand corrected...