2.5 gallon batches

[Vongo]

I have two 2.5 gallon kegs that never get used. The intention was to split a 5 gallon batch up into 2 kegs, store one and drink the other. I have decided to start doing 2.5 or 3 gallon batches and want to use only the 1st runnings. Can I just use the total mash in and sparge volume to do this or do I need to increase the grain bill?
Thanks

 

[Krrazy]

I do three gallon batches all the time. I take a 5gal recipe and multiply each ingredient by 3/5 and mash/sparge as normal calculating my strike, sparge and boil vol as necessary.

 

[Vongo]

So you scale the recipe to 3 gallons and still sparge as you normally would?

 

[Yooper]

So you scale the recipe to 3 gallons and still sparge as you normally would?

Well, you use half the grain and half the volume of mash water, and hence half the volume of sparge water.

 

[Vongo]

I guess what I am getting at is how would I go about doing a no sparge, 1st runnings only brew for a small batch. That make any sense?

 

[Krrazy]

I usually do a single sparge but if I were doing a no sparge three gallon batch I know I would work backwards from the final volume. For my system in dry Arizona, I need 4.5gal pre-boil. I typically mash at 1.25qts/lb and plan for .5 gal of dead space and .1 gal/lb for grain absorption.

Calculate your strike vol. Based on your grain bill, subtract dead space and absorption. That will be the volume if you just drain your mash. Subtract that from your preboil target vol and that will be the extra water you need to add.

 

[Vongo]

Awesome ! Thank you!