BIAB sparge and strike volumes?

[beauvafr]

I am using 15 lbs of grains and a 8 gal pot. Brewtoad mash calculator gives me:

• Strike grains with 4.57 gal of water at 168.9 °F.
• Mash at 155 °F for 60 min.
• Rinse the grain in 3.34 gal sparge water at 168 °F.
• Drain the grain bag and combine the mash and sparge water to make 6.45 gal wort.

I am aiming 75% efficiency and about 6.45 gal pre-boil, to get about 5 gal in the fermenter. I guess this will be faster than doing a mini-sparge.

What do you think? I wonder where the ratio 4.57/3.34 came from in brewtoad..

 

[wilserbrewer]

Looks ok to me. I think the software is trying to make equal the first and second runnings, that's why the strike is more than the sparge accounting for grain absorption of the strike water.

 

[beauvafr]

Looks ok to me. I think the software is trying to make equal the first and second runnings, that's why the strike is more than the sparge accounting for grain absorption of the strike water.

Yeah probably. It makes sense for me too since bringing the water to right temp will be faster. Hope the efficiency will be there.

 

[RM-MN]

From my experience, start with as much water as is reasonable for your pot size. For your pot I might start with 6 1/2 to maybe as much as 7 gallons. More water in the pot means more temperature stability, you won't lose as much heat from the larger amount of water. If you start with sufficient water and your grains are milled fine, you can skip the sparge if you want because you will have in excess of 75% efficiency. Since my pot is 7.5 gallons, starting with the full amount of water usually means that I am close to spilling over the top of the pot when stirring in the grains so I start with a little less and make up for it with a small amount for sparging. That usually picks up another 5% efficiency or more as no matter how hard I squeeze the bag of grains, I always leave some sugars that the sparge will dissolve.

Starting with a smaller amount of water to save a bit of time heating may be self defeating if your mash temperature falls too far.

 

[beauvafr]

I like what RM-MN have to say.

By the way, do you think 4.57 gal is enough to get my 15 lbs of grain submerged?

 

[wilserbrewer]

By the way, do you think 4.57 gal is enough to get my 15 lbs of grain submerged?

Yes, that's over 1 qt/ lb, which is a stiff mash but doable.