First PM: looking for some help

[brigbrew]

I am an extract brewer who was mistakenly shipped a partial mash kit for a Black IPA. I've never done a mash before but I'm game, so I was hoping to get some help from y'all.

The plan is to mash in my brew kettle in a paint strainer, which means I will be mashing with a higher water volume than the recommended 1-1.5 quarts per pound. My first big question is what amount of extract should I add to say...four gallons of mashing water with a gallon and half for sparge, in order to get the PH right for the mash? Or do I have to have the right water/grain ratio.

Here is the recipe:

6 lb Light LME
1 lb Light DME
1 lb Maris Otter
1 lb 2 Row
8 oz Crystal 60
8 oz Crystal 120
8 oz Carafa III

1 oz Galena @ 60
1 oz Galena @ 40
1 oz Cascade @ 20
1 oz Centennial @ 10
1 oz Centennial Dry Hop
Yeast: Safale 05

So, advice?

 

[chickypad]

That sounds way thin, even for BIAB. With that small of a grain bill you'd be over 4.5 qts/lb. Is your pot too big to mash a smaller volume or something? Any smaller pots or drink coolers lying around? Your 3.5 lb grain + 4.25 qts water would take up 1.35 gallons so you just need something big enough to hold that.