First time BIAB gone wrong

[kalmah21]

Hello All! I brewed my first BIAB batch today. This is my first try at all grain brewing. I grabbed a recipe from BeerSmith that looked good (Bell's Two Hearted clone). I scaled the recipe down to 1.5 gallons (shooting for a full gallon at bottling). Beersmith suggested 3.75 gallons for the mash which seems like way too much. The grain bill is only 2.6 lbs. So I tried 3 gallons, figuring for 1 gallon of boil off.

Well, I found that the grains didn't absorb nearly the water I thought they would and boil off was somewhere around 1-2 quarts. The post boil OG was 1.030. It is suppose to be around 1.068. I pitched yeast anyway just to see what it will do, but I'm guessing not much.

Was it just the boil off calculation that resulted in the low OG or should I have been able to pull this off with better efficiency? I mashed in at 160 F which fell to 152 F and maintained for 60 minutes. I then did a mash out, but for some reason I couldn't hit the mash out temp of 168 F until the last couple of minutes. I then squeezed the bag to try to extract as much sugars as possible.

Should I just dump the batch? Am I on the right track for my mashing process? Any suggestions are welcome!

 

[deepcdan99]

Hello All! I brewed my first BIAB batch today. This is my first try at all grain brewing. I grabbed a recipe from BeerSmith that looked good (Bell's Two Hearted clone). I scaled the recipe down to 1.5 gallons (shooting for a full gallon at bottling). Beersmith suggested 3.75 gallons for the mash which seems like way too much. The grain bill is only 2.6 lbs. So I tried 3 gallons, figuring for 1 gallon of boil off.

Well, I found that the grains didn't absorb nearly the water I thought they would and boil off was somewhere around 1-2 quarts. The post boil OG was 1.030. It is suppose to be around 1.068. I pitched yeast anyway just to see what it will do, but I'm guessing not much.

Was it just the boil off calculation that resulted in the low OG or should I have been able to pull this off with better efficiency? I mashed in at 160 F which fell to 152 F and maintained for 60 minutes. I then did a mash out, but for some reason I couldn't hit the mash out temp of 168 F until the last couple of minutes. I then squeezed the bag to try to extract as much sugars as possible.

Should I just dump the batch? Am I on the right track for my mashing process? Any suggestions are welcome!

I use Beer tools and it has never steered me wrong. But it's showing me you would need approx. 4 lbs of grain for a 1.5 post boil at ~1.068, actually it says 1.070. Also calculate 3 gallons single infusion mash would get you to your preboil volume of 2.56 for a 1 gallon boil off. If you only lost 1/2 gallon you could adjust down to 2.5.

Less water boils faster, that may be why your boil off was not 1 gallon. It didn't have the time to evaporate while waiting for it to boil.

Worse case you just made a session IPA, not necessarily a bad thing!!!

 

[monkeyman1000]

I've been using the BIABacus on BIABrewer. I do smaller batches, usually ending up with about 1.75 gallons into packaging. My usual batch requires about 3.3 gallons starting water and about 4.25# of grains on average.

 

[Zzyzx3]

For all the biab batches I've done, I have used this website: http://www.simplebiabcalculator.com/

It is a good calculator for figuring out how much water you will need based on your grain bill, size of your kettle, etc. Beersmith is a great program and provides lots of info and tools for helping you and your brew day. But since you are relatively new to biab, I would say some of the calculators might be a good option for you to check out in addition to Beersmith. Your OG is a bit low, but I would just ride it out and see where it finishes. It will be good practice and you can learn from how this beer turns out to help you in your future biab batches. Good luck!

Good luck!

 

[kalmah21]

Thanks for the advice everyone! I'll ride it out to see what the current batch finishes at and give it another shot as soon as I can free up a fermenter.

 

[RM-MN]

Thanks for the advice everyone! I'll ride it out to see what the current batch finishes at and give it another shot as soon as I can free up a fermenter.

A white plastic bucket at Walmart will cost you less than $5. Add a lid and you're still under $10. Drill a hole in the lid to let the CO2 out, tape a piece of Saran Wrap over it so bugs can't crawl in and you have another small fermenter, good for up to about a 3 gallon batch.

 

[smyrnaquince]

Hello All! I brewed my first BIAB batch today. This is my first try at all grain brewing. I grabbed a recipe from BeerSmith that looked good (Bell's Two Hearted clone). I scaled the recipe down to 1.5 gallons (shooting for a full gallon at bottling). Beersmith suggested 3.75 gallons for the mash which seems like way too much. The grain bill is only 2.6 lbs. So I tried 3 gallons, figuring for 1 gallon of boil off.

Well, I found that the grains didn't absorb nearly the water I thought they would and boil off was somewhere around 1-2 quarts. The post boil OG was 1.030. It is suppose to be around 1.068. I pitched yeast anyway just to see what it will do, but I'm guessing not much.

Was it just the boil off calculation that resulted in the low OG or should I have been able to pull this off with better efficiency? I mashed in at 160 F which fell to 152 F and maintained for 60 minutes. I then did a mash out, but for some reason I couldn't hit the mash out temp of 168 F until the last couple of minutes. I then squeezed the bag to try to extract as much sugars as possible.

Should I just dump the batch? Am I on the right track for my mashing process? Any suggestions are welcome!

First, let me say that knowing your pre-boil gravity would help a lot. Your actual pre-boil and post-boil volumes would help, too.

So, let's make some assumptions and plow ahead.

Assume 37 points/pound of grain:
2.6 lb * 37 = 96.2 points

Assume 75% extraction efficiency
.75 * 96.2 = 72.15 points

Assume 0.2 gal/pound absorption in grain
3 gal mash - (0.2 * 2.6) = 2.48 gal pre-boil

72.15 / 2.48 = 29
Expected gravity pre-boil = 1.029

Boil off 2 qts (= 0.5 gal), leaving 2 gal post boil (rounded)

72.15 / 2 = 36
Expected gravity post-boil = 1.036
You got 1.030 -- close enough! Your efficiency was lower or boil-off lower than what I have above.

So, how do you get where you wanted to be with your desired end volume and gravity?

You wanted a post-boil OG of 1.068
72.15 / 68 = 1.06 gallons post-boil required

Allow for kettle trub and fermenter trub (wild guess here)
1.06 - 0.25 = 0.81 gal into bottles

So, let's back up and squeeze the heck out of the bag, saying that you can get the grain absorption down to 0.127 gal/pound. You now only lose 0.33 gal (instead of 0.52 gal) to the grain.

Add back in that extra 0.19 gal and you get 1.0 gallons into bottles!

Assuming the same trub losses, you need
1.0 + 0.25 = 1.25 gallons post-boil

You say you boiled off 0.5 gallons. I would have expected closer to 1 gallon for a 60-minute boil, but it depends on your setup.

1.25 + 0.5 = 1.75 gallons pre-boil

Allow for water lost to grain absorption, but do a good bag squeeze
1.75 + .33 = 2.08 gallons in the mash

If all the assumptions above were correct (and if my math and process were correct), you should have started with 2.08 gallons of water in the mash.

Try going the the BIABrewer site and asking those guys for the latest version of the BIABacus. It does all the calculations you will need. You'll have to convert quantities to metric, but there is a sheet on the BIABacus spreadsheet to use. The BIABacus usually nails it for me on converting recipes to BIAB and scaling them. (I do 2.5-gallon batches.) It even auto-adjusts your expected efficiency depending on the grain load. Tell them smyrnaquince sent you.

 

[kalmah21]

First, let me say that knowing your pre-boil gravity would help a lot. Your actual pre-boil and post-boil volumes would help, too.

So, let's make some assumptions and plow ahead.

Assume 37 points/pound of grain:
2.6 lb * 37 = 96.2 points

Assume 75% extraction efficiency
.75 * 96.2 = 72.15 points

Assume 0.2 gal/pound absorption in grain
3 gal mash - (0.2 * 2.6) = 2.48 gal pre-boil

72.15 / 2.48 = 29
Expected gravity pre-boil = 1.029

Boil off 2 qts (= 0.5 gal), leaving 2 gal post boil (rounded)

72.15 / 2 = 36
Expected gravity post-boil = 1.036
You got 1.030 -- close enough! Your efficiency was lower or boil-off lower than what I have above.

So, how do you get where you wanted to be with your desired end volume and gravity?

You wanted a post-boil OG of 1.068
72.15 / 68 = 1.06 gallons post-boil required

Allow for kettle trub and fermenter trub (wild guess here)
1.06 - 0.25 = 0.81 gal into bottles

So, let's back up and squeeze the heck out of the bag, saying that you can get the grain absorption down to 0.127 gal/pound. You now only lose 0.33 gal (instead of 0.52 gal) to the grain.

Add back in that extra 0.19 gal and you get 1.0 gallons into bottles!

Assuming the same trub losses, you need
1.0 + 0.25 = 1.25 gallons post-boil

You say you boiled off 0.5 gallons. I would have expected closer to 1 gallon for a 60-minute boil, but it depends on your setup.

1.25 + 0.5 = 1.75 gallons pre-boil

Allow for water lost to grain absorption, but do a good bag squeeze
1.75 + .33 = 2.08 gallons in the mash

If all the assumptions above were correct (and if my math and process were correct), you should have started with 2.08 gallons of water in the mash.

Try going the the BIABrewer site and asking those guys for the latest version of the BIABacus. It does all the calculations you will need. You'll have to convert quantities to metric, but there is a sheet on the BIABacus spreadsheet to use. The BIABacus usually nails it for me on converting recipes to BIAB and scaling them. (I do 2.5-gallon batches.) It even auto-adjusts your expected efficiency depending on the grain load. Tell them smyrnaquince sent you.

WOW! Thanks for the detailed explanation! This helps confirm that I used too much water in the mash. I found this formula over on another forum for estimating boil off according to the radius of my brew pot: (r² x 3.14)/150. The number for my brew pot came in a little over 2 quarts, so pretty close to what I saw for actual boil off. I have found and used a couple of BIAB calculators and they come up with a number close to the 2.08 gallon mash volume that you calculated. I do have one question. Is 37 points/pound an average number that can be assumed for all/most grains?

 

[smyrnaquince]

I think 37 ppg is a 2-row malt number. Different grains are different.
Some ppg's are listed here.

 

[kalmah21]

Thanks!