Biab fail!

[SteveH aka shetc]

I cannot recommend this site enough www.biabrewer.info . The participants include some of the original Aussie developers of BIAB.

 

[McKnuckle]

I would put betting money on the crush. There is just no reason to nitpick all the other stuff - mash density, mash temp, etc. - because I and many others have varied those elements with no significant efficiency loss. Mashing in a bag is just not that different from mashing without a bag. It's a bag! The BIAB process is treated as something so different, but it's just... well, not.

I'll be another annoying person to chime in and say that I routinely get 80% or better with a full volume BIAB mash, using temps anywhere from 147 to 160 in a standard 60 minute mash. I only stir at mash-in and before draining, and I gravity drain with no bag squeezing.

In fact I put your 5.25 gallon target and 10.5 lbs of grain into my own trusty spreadsheet, adjusted the total water volume to about 7 gallons (which is what you used), and in order to get an OG of 1.030 I needed to lower mash efficiency down to 42%. That's extremely low; I couldn't even approach that if I tried. But... I crush my own grain. It's gotta be the difference.

If you read the perennial BIAB threads complaining about efficiency, it's always crush, crush, crush that gets mentioned. I only mill once, too.

Maybe show a photo of your crush next time you get some grain milled?

 

[ArcLight]

#1 TIGHT CRUSH

#2 - I get >10% higher efficiency with a dunk sparge. Mash in less water, and put the bag in a second pot and add the remaining water. The ratio of water isn't 50/50, its more like 60/40.

#3 mash cooler, 155-160, is a bit high - unless you have a super fine crush with instant gelatinization and conversion in 2 minutes. Beta Amylase gets denatured quickly at 160.

 

[McKnuckle]

I just want to point out that a higher mash temp shouldn''t affect the OG reading. Alpha amylase quickly converts the grain's starches to long-chain sugars at higher mash temps. Beta amylase, which acts more slowly, breaks down the liberated long-chain sugars into fermentable simple ones. However, even if that latter process is completely halted (which doesn't happen even at 160F), the long-chain sugars will still register in the gravity reading.

The well-known Lagunitas IPA is mashed at 160F, FWIW.

One thing I've found in BIAB is that the more closely the bag fits the mash vessel, the more predictable the result. It should ideally be like a second skin to the tun/kettle walls, not to the grain. This limits the amount of water floating around the bag vs. in the bag with the grain where it belongs.

 

[balrog]

+1 on bag size; the better the grains and water mix, the better the process works.

Size matters.

 

[eadavis80]

Masskrug - when I used that calculator, it said that the mash + grains would be a higher volume than my kettle... = spill, I'm guessing.

 

[doug293cz]

Masskrug - when I used that calculator, it said that the mash + grains would be a higher volume than my kettle... = spill, I'm guessing.

If that's the case, you need to increase the volume of the sparge until you get the mash volume down to 0.5 to 1 gal less than the kettle volume.

Brew on

 

[Bobby_M]

I'm not crazy about double crushing because you can achieve the intended result by cranking the gap closer instead. Double crushing shreds the hell out of the husks for no reason. My shop Monster Mill has the flange style gap adjusters and I installed large handle set screws that allow me to adjust the gap over and over with relative precision since I made a few index marks. Basically I have a coarse, medium, and BIAB gap mapped out. Customers that ask for a double crush get the BIAB setting and it's a lot of flour with still relatively intact husks. I adjust the mill almost every time I use it many times a day.

 

[pricelessbrewing]

Masskrug - when I used that calculator, it said that the mash + grains would be a higher volume than my kettle... = spill, I'm guessing.

Calculator maker here, yes if your mash volume is higher than your kettle volume you're going to have a big mess on your hand. I like to leave a half inch of room at least to stir and dough in well.

All good advice, it's almost always the crush btw. Stirring helps. I stir very thoroughly during dough in, and again before I pull the bag. I average about 75% fwiw.

Thanks for being a good lhbs then bobby! From my experience, 3 lhbs, two of them didn't let us adjust the mill settings. One does, but gives bad advice about how to use it. (don't go below this mark, or Blah blah blah will happen, and crush dark grains barely at all cuz "unfounded homebrew science reasons"). I crank it down as far as his knob will let me, then run it through again. It's still not quite as fine as I'd like, but good enough for me to not buy a mill. When I move, if the lhbs won't let me adjust the mill gap I'll probably buy a corona mill.

 

[eadavis80]

WEll, my next attempt at BIAB will be next week. I have NB's Dead Ringer on hand. It's supposed to yield 3 gallons of 1.064 wort. They say to start with 5.5 gallons of water. Last time I did this, with their suggested 60-minute boil, I ended with 4.25 gallons of 1.042 wort. So, this time I will try a few things per all of your welcome suggestions:
1. Be sure to watch my mash temp and make it as close to 152 as possible as I might have been a little warm last time.
2. Mash for 90 minutes
3. Squeeze the bag before letting it drip into the brew kettle
4. Do a dunk sparge with 165 degree water.
5. Squeeze the bag again

If this doesn't result in a better efficiency, I won't know what else to do...

 

[TexasWine]

WEll, my next attempt at BIAB will be next week. I have NB's Dead Ringer on hand. It's supposed to yield 3 gallons of 1.064 wort. They say to start with 5.5 gallons of water. Last time I did this, with their suggested 60-minute boil, I ended with 4.25 gallons of 1.042 wort. So, this time I will try a few things per all of your welcome suggestions:
1. Be sure to watch my mash temp and make it as close to 152 as possible as I might have been a little warm last time.
2. Mash for 90 minutes
3. Squeeze the bag before letting it drip into the brew kettle
4. Do a dunk sparge with 165 degree water.
5. Squeeze the bag again

If this doesn't result in a better efficiency, I won't know what else to do...

Might I suggest only changing one variable at a time? Otherwise how will you know what fixed the problem?

Personally, I don't think your mash time is the culprit. If it isn't then you just added more time to your brew day for no benefit.

And just so you know, last time you made Dead Ringer, if you would have kept boiling that 4.25 gallons of 1.042 wort down to 3 gallons you would have hit a 1.060 OG. Pretty stinking close to the 1.064 you were going for. Since you ended up with more volume than you wanted it sounds to me like your boil off rate number is askew or your started your boil with a higher volume than you should have.

This is exactly why you should take multiple gravity and volume readings all along the process of brewing. If you see you have more volume than you wanted, but your gravity is spot on for said volume, then you can just boil longer to get rid of the excess water and adjust your hop additions to coincide with the new schedule.

I've found that brewing sometimes requires being able to adjust when things don't go as planned. Taking these readings will help you do that.

 

[madscientist451]

I agree with TX wine above that the 90 min mash isn't really necessary. What jumps out at me is that your numbers or your volume measurements are way off. You have stated that you started with 5.5 gallons of water, then after mashing and 60 min boil there is 4.25 gallons? So evaporation and grain absorption accounted for only 1.25 gallons? Just a guess, but I'm thinking you started with more like 6.5 gallons.
Ok my coffee hasn't kicked in yet or maybe I missed something, but if your initial water measurements are off, that would account for final volume and gravity issues. Good Luck, hope next brew comes out better...

 

[eadavis80]

Say after my 60-minute boil (if I do that instead of 90 per your suggestions) I'm still at say 3.75 gallons instead of my target 3.25 (figure .25 gallon to trub), can I just boil off until I get down to that 3.25 gallon mark? Also, if I do an iodine test to check for conversion pre-boil, will that tell me anything about OG, or is it just simply going to tell me starches have converted to sugars, but how much sugar is really in that wort is an unknown? Lastly, if I take a pre-boil gravity reading to specifically check gravity at that stage in the brew process, do I just find a way to cool that sample real quick so it's close to 60 degrees? Obviously, the hydrometer sample right out of the brew kettle would be around 165, if I do the optional mash out.

 

[IslandLizard]

Good suggestions given here.

If you have any whole kernels in your grist and pieces larger than 1/8" you need a much better (and finer) crush.

Milling 2x is not an alternative to once done right!

I'm with Bobby_M on adjusting the gap to your grains and purpose. For example, Wheat and Rye berries are very small, and need a very tight gap. Most LHBS don't give an S, and just mill fassst and way too coarsely.

Get a knock off Corona mill for $25 if you don't want to invest in a decent roller mill and you're in control of your crush.

 

[McKnuckle]

Definitely heed the wise words here about water volumes and evaporation. Getting one's expected OG is based on mash efficiency AND evaporation. This is why it's very useful to measure pre-boil gravity if you can, using a refractometer or a chilled sample in a hydrometer. That gravity tells you your mash efficiency in purest form.

I frequently get higher mash efficiency than expected, but boil-off less than I expected, resulting in hitting my target OG fairly closely. One misjudged factor compensates for the other. Even though it's the desired end result, it's annoying!

 

[balrog]

do I just find a way to cool that sample real quick so it's close to 60 degrees? Obviously, the hydrometer sample right out of the brew kettle would be around 165, if I do the optional mash out.

I put a ceramic cereal bowl in freezer at Time=0 on brewday.
When it's time to measure with hydrometer (have since gotten refractomer) I take sample, remove frozen bowl, pour in sample, swish, put in graduated cylinder and temp is reasonably cool. One man's method.

 

[eadavis80]

I put a ceramic cereal bowl in freezer at Time=0 on brewday.
When it's time to measure with hydrometer (have since gotten refractomer) I take sample, remove frozen bowl, pour in sample, swish, put in graduated cylinder and temp is reasonably cool. One man's method.

Nice tip! Thanks!

 

[TexasWine]

can I just boil off until I get down to that 3.25 gallon mark?

Yup

EDIT: If you've got a good number for boil off rate, you should know if you're going to end up with too much volume after 60 minutes of boiling BEFORE you even start your boil. So let's say you had 0.5 gallons too much before the boil starts and your boil off rate was 1 gallon per hour. You'd boil 30 minutes to get to the proper starting volume, and THEN proceed with your hop additions as normal.

Also, if I do an iodine test to check for conversion pre-boil, will that tell me anything about OG, or is it just simply going to tell me starches have converted to sugars, but how much sugar is really in that wort is an unknown?

Iodine test will only tell you if you've had conversion. Take a reading with your hydrometer to get the gravity. Or better yet, get a refractometer.

Lastly, if I take a pre-boil gravity reading to specifically check gravity at that stage in the brew process, do I just find a way to cool that sample real quick so it's close to 60 degrees? Obviously, the hydrometer sample right out of the brew kettle would be around 165, if I do the optional mash out.

Yup. Someone has already chimed in on this one I see.

 

[madscientist451]

Say after my 60-minute boil (if I do that instead of 90 per your suggestions) I'm still at say 3.75 gallons instead of my target 3.25 (figure .25 gallon to trub), can I just boil off until I get down to that 3.25 gallon mark?

No one suggested a 60 minute vs/90 minute boil. The comment was about mash time.
But to answer the above question, if you get 3.75 gallons instead of 3.25, its not worth worrying about as long as you are hitting the gravity target.
If the gravity is too low, you can keep on boiling, but if your beer has late hop additions, the continued boil will drive off hop flavor and aroma, so you need to figure out your system so you don't have to do that.
Are you carefully measuring your water? I use 1 gallon jugs to measure water when I'm brewing, but I use well water from my G/F's house and start with a certain number of jugs so I know exactly how much I'm using.

 

[eadavis80]

No one suggested a 60 minute vs/90 minute boil. The comment was about mash time.
But to answer the above question, if you get 3.75 gallons instead of 3.25, its not worth worrying about as long as you are hitting the gravity target.
If the gravity is too low, you can keep on boiling, but if your beer has late hop additions, the continued boil will drive off hop flavor and aroma, so you need to figure out your system so you don't have to do that.
Are you carefully measuring your water? I use 1 gallon jugs to measure water when I'm brewing, but I use well water from my G/F's house and start with a certain number of jugs so I know exactly how much I'm using.

My mistake - I MEANT 90 minute MASH, not boil. But yeah, I was thinking about that with the late hop additions possibly being a problem if I continued to boil in order to raise the gravity of the remaining wort.

 

[Gavin C]

If this doesn't result in a better efficiency, I won't know what else to do...

Crush finer. NB crush is much coarser than I use. (single pass at my mills narrowest setting) To quote @wilserbrewer I believe, "Looks like coarse corn meal".

 

[dbj]

Has anyone ever asked an online brew store to double crush? If so, did you have any luck?

Farmhouse Brewing Supply has a selection for double crush. I think it's 10 cents more per pound.

 

[Brew_G]

Lots of great advice here. Good luck!

Definitely heed the wise words here about water volumes and evaporation. Getting one's expected OG is based on mash efficiency AND evaporation. This is why it's very useful to measure pre-boil gravity if you can, using a refractometer or a chilled sample in a hydrometer. That gravity tells you your mash efficiency in purest form.

I frequently get higher mash efficiency than expected, but boil-off less than I expected, resulting in hitting my target OG fairly closely. One misjudged factor compensates for the other. Even though it's the desired end result, it's annoying!

This is exactly what happened to me this past Saturday. This was the first time I've taken pre-boil gravity, and I ended up at 1.058 v. the expected 1.055. After the boil, my OG was 1.065 v. expected 1.064. I'm not complaining about the end result, but I'd much rather have just ended up with an OG .003 than planned!

 

[eadavis80]

Well, my most recent attempt was improved on a number of levels. Learning as I go:

1. Took a pre-boil gravity reading and it was 1.042, which was my post-boil last time.
2. Did an iodine test and had successful conversion after the 60-minute mash.
3. Started with 4.5 gallons of water instead of 5.5
4. Squeezed the bag quite a bit after the 60-minute mash.
5. Then did a dunk sparge into 170 degree water and stirred it there and squeezed the bag again after the dunk sparge.
6. Emptied dunk sparge wort back into BK and started the boil with just over 4 gallons of volume.
7. Was able to transfer to fermenter about 3.5 gallons of wort which should yield just over 3 gallons of beer after trub settle/dry hopping.
8. Sample tasted better than last time.
9. Next week is Oktoberfest BIAB with 2112. These grains were crushed by my LHBS so it will be interesting to see if they crushed finer than NB. In looking at the two bags of grain, they looked pretty similar to me - maybe a little finer at the home brew store as I asked for a pretty fine crush.
10. Yesterday's OG sample taken after cooling wort was 1.050. Still not the 1.064 NB posts on the recipe, but much better than my previous OG.
Thanks guys!

 

[TexasWine]

Well, my most recent attempt was improved on a number of levels. Learning as I go:

1. Took a pre-boil gravity reading and it was 1.042, which was my post-boil last time.
2. Did an iodine test and had successful conversion after the 60-minute mash.
3. Started with 4.5 gallons of water instead of 5.5
4. Squeezed the bag quite a bit after the 60-minute mash.
5. Then did a dunk sparge into 170 degree water and stirred it there and squeezed the bag again after the dunk sparge.
6. Emptied dunk sparge wort back into BK and started the boil with just over 4 gallons of volume.
7. Was able to transfer to fermenter about 3.5 gallons of wort which should yield just over 3 gallons of beer after trub settle/dry hopping.
8. Sample tasted better than last time.
9. Next week is Oktoberfest BIAB with 2112. These grains were crushed by my LHBS so it will be interesting to see if they crushed finer than NB. In looking at the two bags of grain, they looked pretty similar to me - maybe a little finer at the home brew store as I asked for a pretty fine crush.
10. Yesterday's OG sample taken after cooling wort was 1.050. Still not the 1.064 NB posts on the recipe, but much better than my previous OG.
Thanks guys!

Something that stands out to me. You started the boil with 4 gallons and you got 3.5 to the fermenter. Just to make sure, you only lost 0.5 gallons during the 60 minute boil? Did you leave anything behind in the kettle when your transferred? If so, you lost even less than 0.5 gallons!

And your pre boil reading, was it after sparging so you had 4 gallons at 1.042?

 

[eadavis80]

1. I started with 4.5 gallons, not 4, as stated in no. 3 above
2. Yes, the pre-boil reading of 1.042 was read from 4-gallons of wort. The sample had been cooled to probably 65 degrees.

 

[McKnuckle]

"Started with 4.5 gallons" is a little vague.

You started MASHING with 4.5 gallons, or you started BOILING with 4.5 gallons of collected wort?

I think it's the former - you mashed with 4.5, lost 0.5 to absorption and MLT, and you collected 4 gallons of wort. You boiled that down to 3.5 gallons (0.5 gal evaporated in one hour).

Have a look at this to see how evaporation affects your OG based on your pre-boil gravity:
http://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/

 

[eadavis80]

Okay, I see the confusion now.
I put 4.5 gallons of water in the brew kettle to start my brew day. Therefore, I MASHED with 4.5 gallons, not the 5.5 gallons I mashed with on the prior attempt.
I started BOILING with right around 4 gallons of wort.
Thanks for the calculator tip! I've toyed around with a few calculators from them, but did not know about that one

 

[TexasWine]

6. Emptied dunk sparge wort back into BK and started the boil with just over 4 gallons of volume.

Just want to make sure we're all on the same page here, but it sounds like you started your boil with 4 gallons, not 4.5.

4 gallons sounds about right if you got 1.050 as a post boil reading. I calculate 1.048 if you take 4 gallons of 1.042 down to 3.5 gallons. So maybe you had a smidgen over 4 gallons to start?

If your boil would have started with 4.5 gallons and you boiled down to 3.5, you would have had an OG around 1.054 or so.

EDIT: Just saw you figured it out before I could chime in.

 

[kh54s10]

I am somewhat lost with all the volumes and gravities given. But, collecting the proper volume is critical. If the recipe calls for a final volume of 3 gallons and you are collecting 3.5 gallons your gravity will be low. I think you may be accounting too much to trub loss. I lose less than a quarter gallon to trub in a 5 gallon batch. I do use a 5 gallon paint strainer bag to contain hop debris.

Keep adjusting your volumes until you end up with the predicted amount of wort going into the fermenter without leaving much if any in the boil kettle. I leave only the thickest part in the BK, less than 12 ounces.