Convert Extract to Partial

[msmith92]

I have a NB kit recipe for a British Bitter. I'd like to do it as a PM using my 20 quart kettle and brew bag. Looking to do a 5 gallon batch.

O.G: 1.035 READY: 4 WEEKS
2 weeks primary, 2 weeks bottle conditioning
KIT INVENTORY:
SPECIALTY GRAIN
-- 0.5 lbs Simpsons CaraMalt
FERMENTABLES
-- 1 lbs Golden Light dry malt extract (60 min)
-- 3.15 lbs Maris Otter malt syrup late addition (15 min)
HOPS & FLAVORINGS
-- 1 oz UK Kent Goldings (60 min)
-- 0.5 oz UK Kent Goldings (15 min)
-- 0.5 oz UK Kent Goldings (1 min)

 

[Yooper]

You could use some two-row in place of the extract. I'd use maris otter. The replacement is 1 pound two-row = .75 pounds LME = .6 pound DME so you could simply replace some of the extract with grain.

How much can you mash?

 

[msmith92]

I've only done one partial mash using a kit from ABH and I followed their instructions which had me doing a 2 - 2 1/2 gallon mash in a 5 gallon kettle.

I used a large grain bag and kept the temp steady in my oven. Worked great.

 

[nucciocioccio]

You can replace Maris Otter syrup with grains, mash them with the caramalt (154 F temp), and see the OG you achieve. One and half quart per pound means you could mash up to 10 pounds grains, boiling 15 quarts. Given a 75% efficiency, you will only need 5 pounds Maris Otter to achieve your OG. I would say mash your 5 pounds in 8 quarts, boil it with hops, adjust with extract as a function of the efficency you got (you'll need some software, or to make some calculation).
I think there's no need to adjust the hops, as you'll probably have a very close IBU value to the extract recipe goal, boiling in a lower OG water.
So here's the recipe I've thought:

5 lbs Maris Otter Pale Malt
0.5 lbs dry malt extract (more or less, depends on your efficiency)
Hops the same.

boil in 8 quarts, DME as late addiction (i'd boil it for few minutes with 2 or 3 quarts of water in a separate pot and add to the wort in the fermeter) top up fermenter to 5 Gal, pitch yeast, wait, worry about your fermentation not starting, relax and wait.

 

[msmith92]

You could use some two-row in place of the extract. I'd use maris otter. The replacement is 1 pound two-row = .75 pounds LME = .6 pound DME so you could simply replace some of the extract with grain.

How much can you mash?

So, if I had 3.3 lbs of Excract I'd need 4.4 lbs of grain to replace it?