BIAB mash calculator

[Beer-lord]

As I have had some trouble with Beersmith, though I think I have it tweaked now after 4 boils in my new kettle, I use this calculator today..
http://www.copycalc.com/bob/BIAB
I'm still in my boil stage but it looks spot on for water amounts. It was only off one degree for my mash temperature but that was likely because I had the grain temp too high.
It's close to Beersmith but so far, seems to be more accurate for me and my pot. Simple to use and simple to understand and that fits in my KISS brewing principles.

[duff]

I like that website.

I had a lot of problems getting brewsmith configured and I gave up but that site works well.

[John Sand]

Thanks!

[losman26]

Using beersmith for BIAB, I have been way off every time. Maybe I have to figure out the exact size of crushing my grain. One batch I crushed it at .025 and over-shot my boil gravity by a lot, but I was crushing grains that were already crushed with this setting. For the next batch, I raised the settings slightly crushing it only once, and undershot my FG by 6-7 points. I'm going go back to .025 for the next batch, only crushing once to see where it lands.

[russki]

Another good one is http://simplebiabcalculator.com

[ScrewyBrewer]

I was looking at the BIAB calculator at http://www.copycalc.com/bob/BIAB and was wondering if anyone knew the formulas behind the calculators?

For grain absorption I used the formula of 12.5 x 0.13 = 1.65 gallons of water
For mash thickness I used the formula of 12.5 x 1.20 = 15 quarts or 3.75 gallons
Combined water totals 1.65 + 3.75 = 5.4 gallons and add another gallon for boil loss comes out to about 6.4 gallons for the preboil.

I get that they ask you for the weight of the grains and the temperature but why is there no mention of your desired mash thickness? Is that not important when doing BIAB? Their preboil volume comes out to 6.4 gallons but their mash thickness is 2.3 qts/lb were my calculations 1.5 qts/lb.

I don't mean to give anyone a math test or make their heads hurt so early in the day, but I was just curious if anyone else had any thoughts on this.

[russki]

With BIAB, you use the total water volume (strike and sparge combined) from the get-go, that is why mash thickness is not a variable. At the end of the mash, you just remove the bag (some squeeze it, I don't), and proceed with the boil.

[jhough]

I have been using Brewmate . Used Beer Formulator but you need to be careful with mash temps and sparge water. Strike temp has always been 2-3 * too high on mash temp.

[jhough]

OOPS forgot to say I do batch sparge not full volume mash.

[ScrewyBrewer]

With BIAB, you use the total water volume (strike and sparge combined) from the get-go, that is why mash thickness is not a variable. At the end of the mash, you just remove the bag (some squeeze it, I don't), and proceed with the boil.

Thanks for explaining, I don't think I'll be falling into the 'squeezers' category either, based on what was gospel early on in my brewing days.

Maybe you can explain another concept. In single infusion mashing I calculate the weight and temperature of the grains and my target mash temperature to get the strike water temperature.

This is a pretty basic question but how does RIMS BIAB get the mash to the target temperature? Do I heat the water to say 168F before filling the bag with 70F grains to get a 155F mash temperature?

[Beer-lord]

Since I have no way of lifting my bag with 15 or more pounds of grain, I strain some into 2 other bags in buckets. Takes about 10 minutes.....and I use the spoon to get lots of liquid out. Usually about a half gallon. Then I adjust my boil time for the amount that's more than what my software calculates and usually (still tweaking this with the new pot) I come close.

[frogmeat69]

Another good one is http://simplebiabcalculator.com

That's the one I've used, works good!!

[losman26]

After using beersmith on my last batch, and being off with my FG by 5 pts, I'm going to use one of these two calculators.
Looking at these two calculators, I'm unsure as to what the evaporation/boil off rate should be? Is the normal evaporation rate 10% per hour? This is the default in the first calculator. For the simpleBIAB it asks to put in gal per hour. I have it set at 1 gal per hour but am unsure. Looking at my beersmith settings, it is saying 17.6% evaporation rate, which could explain why my FG was too low on the last batch.

I know that it is probably impossible to get an exact evaporation rate, but what would be a good estimate for a 20 quart pot with a 12 inch diameter?

Also, is the finished beer amount, the amount at bottling/kegging time?

My grain bill is like this-
6.75 lbs grain
2.54 oz hops

boil- 90 mins
boil off 1 gal/hr

finished beer 2.28 gal (according to beerSmith)
Fermentation trub-.51 gal

Kettle diameter 12 inches
mash temp 147.9


Ok another confusing aspect of the simpleBIAB calculator is the mashout. When I plug in the numbers, it says to use 3.66 gal mash water, and 1.57 gal mash out water. What exactly do they mean by this? I always thought that mashout in BIAB, simply meant raising the temp to 168 F.

[Beer-lord]

They've updated the calculator in my first post. This one doesn't use 10% and allows you to set your own boil off rate.
http://www.copycalc.com/bob/BIAB%20Fixed%20Boil%20Off

For me and my setup , I boil off just a tad bit more than a gallon per hour. Humidity plays a part as well since you'll lose less than if the air was drier.

[losman26]

They've updated the calculator in my first post. This one doesn't use 10% and allows you to set your own boil off rate.
http://www.copycalc.com/bob/BIAB%20Fixed%20Boil%20Off

For me and my setup , I boil off just a tad bit more than a gallon per hour. Humidity plays a part as well since you'll lose less than if the air was drier.

I just never really paid attention to the boil off rate or measured it. I'm really unsure as to where I should set it. 17% where beersmith had it, seems way too high where it was before. I do know that for my extract brews, beerSmith was exactly right on. For my BIABs, it has been off. For the last batch, I ended up with almost 1 gal extra and used the extra beer in a one gal jug. I also was at 1.057 instead of 1.061 where I wanted to be.