BIAB calculator challenged......
 

i have taken the grain wt and hop schedule, mash in temps and boil volume & boil time from the sticky tutorial on BIAB brewing and used them with the BIAB calculator but i do not arrive at the 7.5 gallons of water as @ the tutorial recipes states.
the biab calculator shows me water volume 9.91
strike temp 152,47 for a 154 mash?
post boil volume 7.07 gallons not the 5.5 as @ recipe.

can some one tell me what i'm doing wrong?

thanx:(
GD51

There are several calculators... which one are you using (link please)?

How many pounds of grain in the recipe?


If you are using beersmith as your calculator, you should know up-front that it gets that stuff all wrong.

thanx for the reply........this is the link:http://www.simplebiabcalculator.com/

:mug:GD51

this is from the sticky in the all grain /partial mash topic line :

Modified Recipe
--------------------------
Recipe Type: All Grain
Yeast: Irish Ale (Wyeast Labs #1084)
Yeast Starter: Yes
Batch Size: 5.50 gal
Boil Size: 7.50 gal
Estimated OG: 1.056 SG
Estimated Color: 34.2 SRM
Estimated IBU: 16.3 IBU
Brewhouse Efficiency: 70.00 %
Boil Time: 60 Minutes
Mash In: 60 Minutes with 7.50 gal of water @ 159.3 F
Mash Out: 10 Minutes with 0.00 gal of water at 170.0 F

Ingredients:
---------------
9.00 lb Pale Malt (2 Row) US (2.0 SRM)
1.00 lb Barley, Flaked (1.7 SRM) Grain
1.00 lb Roasted Barley (300.0 SRM) Grain
0.75 lb Caramel/Crystal Malt - 20L Grain
0.50 lb Caramel/Crystal Malt - 40L Grain
0.50 lb Chocolate Malt (350.0 SRM) Grain
0.70 oz Cluster (60 min) Hops
1.00 oz Goldings, East Kent (10 min) Hops
0.25 oz Williamette (2 min) Hops
8.00 oz Cocoa Powder (Boil 5.0 min) (pre-mixed with hot water)
1 Pkgs Irish Ale (Wyeast Labs #1084) Yeast

Total Grain Weight: 12.75 lbs

:mug:
GD51

OK well the grain is going to absorb about 1.25 gallons of water (actually a bit more), assuming you squeeze the bag pretty well and collect the runoff. So that means you need at a bare minimum:

5.5 (batch size) +
1.25 (losses to grain absorption) +
1.0 or more (boil-off)
----
7.75 gallons, assuming you have absolutely no trub losses (fat chance) and boil off water at exactly 1 gallon per hour...that really depends on your particular system.

On my system (which does boil-off pretty close to 1 gallon per hour), I would use more like 8.25 gallons to account for trub losses, a bit of spillage, and the wort that remains in the hoses & chiller after transferring to the fermenter.

I usually just sort of estimate my strike water temp, but I would probably heat the strike water to about 157F or so and stir in the grain. You may end up a bit low or a bit high, but it is pretty easy to make small temperature adjustments in BIAB, which is why I don't worry about dialing it in too accurately.

I entered all your info into the calculator and got 7.91 gallons, 161.85 strike temp, for a 5.25 gallon batch.

Dang, I've been doing this BIAB thing all wrong. I just made two batches with about 11 pounds of grain each using full volume for mashing and managed to fit it all into my 7 1/2 gallon pot. By the end of the boil I had about 5.25 gallons of wort. Now explain to me how I fit the 9.91 gallons (shown in the OP's first post) or even the 7.91 gallons shown in post #7 into my 7 1/2 gallon pot.

I use Tasty brew for all my calculations and have always been accurate. (strike temp, mash volume, etc) If you are geting bad numbers, perhaps its time to build your own spreadsheet. That's what I did. Not because I mistrust the online calculators but because my brain needs to process the raw data and understand where they are coming from. The math is not complicated, and I believe it makes me a more intuitive brewer.

Not really... You have to set up Beersmith correctly for BIAB. It takes some testing for your equipment but the Beersmith website shows you how to dial it in.

There are more than a few ways to BIAB but if you really want to true BIAB, you need to add all of your water up front. Which means my 8 gallon pot doesn't usually work for a full 5 gallon brew with a sizeable grain bill. But, you can easily modify it by using a couple of kettles and sparging, doing sort of a partial boil or tossing in a bit of DME or LME to make up the difference so you can use your 7.5 gallon pot. I also scale some of my recipes down a bit to a 4 gallon just so I can use a smaller pot. But that means less beer... But in my case, I also do 1-2 and 3 gallon batches so I can have a variety.