BIAB Milling Success and Brew Day Almost Failure

[brew-bandit]

Happy New Year all!

I have been experimenting with milling and its impact on my beer and process. I have a Monster Mill 3 and set it up with a gap of .025in. I brewed and Irish Red yesterday with a 90 min mash at 147 degree F. Everything looked fantastic and Brewsmith predicted my OG as 1.051 and I achieved 1.061. This brought my total efficiency up to ~88%! I am not one to care much but was astounded to see it go up to 88% up from my typical 75%. It is also largely attributed to the 90min low temp mash.

I am considering reducing the gap on the mill maybe to .020in. What's the lowest anyone has gone?

Once the wort was cooled I racked it to a 6.5 gal glass carboy. After I had transfer a little more then half I noticed beer on the ground around the carboy. My carboy had cracked!!!!! I stopped the transfer and cleaned up the massive mess of beer all over the backyard then I quickly drilled a hole in lid of my bottling bucket. Sanitized, transfer about 2.5 gal, pitched the yeast and popped in the airlock.

Hopefully I managed to salvage a couple of gallons and if it turns out good I will make another full batch. Also I think I am discontinuing using glass fermenters.

 

[DeeEnvy]

That was a good save.
I have used glass for many years and never had one crack. Not to say it won't happen. I put my carboys in a plastic milk crate just in case.
I have set my mill to .032" for BIAB and leave it there. This produces an efficiency of between 75 and 80% consistently. No need for double grind or a smaller grind. YMMV

 

[IslandLizard]

Sorry about your carboy mishap. That really sucks. Just be glad you didn't get injured!
I only use carboys now for long term (sour beer) aging, less handling. Plastic buckets for regular fermentations. Secondaries, only if absolutely needed, are done in kegs. Easier to purge the air from, and any volume will work.

Congrats on your MM3!
0.025" is a great setting, even for smaller kernels (wheat, rye) and flaked goods. You could try a little finer, sure, but I doubt it will raise your efficiency. 88% is darn good already! I trust you do a dunk sparge?

 

[Foosier]

I don't think your high efficiency is a result of the long mash. I routinely get high efficiencies with a double crush and 60 minute mash. Your very fine crush is likely the chief reason for the high efficiency. Many have done experiments with BIAB to see how long conversion takes and some have found it complete within 10-15 minutes with an extremely tight grind (flour).

The benefit of a longer mash is primarily in getting more sugars to come out of the grain. If you have crushed fine, this won't take that long since the fine crush increases surface area and reduces the distance the sugar has to travel to reach the wort. If you use a more coarse crush a longer mash could increase extraction but it would not necessarily speed conversion as the enzymes work fairly quickly.

 

[IslandLizard]

@Foosier A double crush at a gap that's too wide is still far inferior to a single crush done at the correct gap for your system. The small kernels simply don't get crushed!

I've seen people leave the brew store with a "double crushed" barley and wheat mix containing lots of uncrushed wheat kernels. Then when they drink it they wonder why the beer is called a wheat.

 

[doug293cz]

+1 to @Foosier . This is the basics of grind vs. time & efficiency.

I grind with a mill gap of 0.016" (0.4 mm). No problems yet.

OP: Sorry for your loss. I gave up glass carboys immediately after finding one of the "carboy horror story" threads on HBT.

Brew on

 

[brew-bandit]

Good points Foosier. I have not been daring enough to try the 15-30 min mash but may soon.

Here is an experiment on crush and BIAB that inspired me to start a more aggressive crush.

http://brulosophy.com/2015/11/23/mind-the-gap-course-vs-fine-crush-exbeeriment-results/

IslandLizard - I actually don't dunk sparge at all. I full volume mash and then drain/squeeze up to pre-boil volume. I have been aiming at 6.25 gallon batches because I usually lose about 1 gallon to trub in fermentation. I dump the whole kettle in the fermenter.

I have 2 problems with the glass carboys, one is that they are space hogs for storage, the second is sensitivity to temp changes. I have broke 2 in the last month and it is due to temp changes. So it is really my fault and I can resolve the issue by being more careful but I am not sure I care enough to keep the glass carboys.

 

[TexasWine]

I've gone as tight as 0.010, but eventually settled on 0.025 as my go to for normal BIAB.

But then I got a recirculating eBIAB system and was having problems with the mash circulation. Today loosened my mill to 0.040 and got 86% brewhouse efficiency. However, I did a two step mash today, 60 minutes at 142F, 30 minutes at 158F. So total mash time over 90 minutes. I think 0.040 is the sweet spot for me.

And I only use plastic carboys now, and those only for wine. Well, with the exception of the one glass carboy I kept to do vacuum degassing of my wine.

 

[pricelessbrewing]

Lots of good comments. I did the same thing doug, sold off my carboy last winter. Will never buy one again. Buckets for fermenting beer, kegs for aging beer.

@ mash time. Do you have a refractometer, if so taking gravity readings throughout the mash to find out how long it actually takes to convert is a great technique that not enough people do. I'm a big fan for it especially for new brewers or those trying a new setup.

 

[brew-bandit]

Priceless - you read my mind on testing during mash. I was thinking I would go for shorter mash times and measure while mashing. I am going to pick up a refractometer before my next batch.

 

[pretzelb]

Lots of good comments. I did the same thing doug, sold off my carboy last winter. Will never buy one again. Buckets for fermenting beer, kegs for aging beer.

@ mash time. Do you have a refractometer, if so taking gravity readings throughout the mash to find out how long it actually takes to convert is a great technique that not enough people do. I'm a big fan for it especially for new brewers or those trying a new setup.

I should do a new thread but does anyone have tips on taking samples? I just open the valve on my mash tun but I wonder if readings from the top of bottom make a difference.

My last few brews showed the gravity increasing after 60 minutes so I'm suspect that I'm doing something wrong.

 

[Foosier]

@Foosier A double crush at a gap that's too wide is still far inferior to a single crush done at the correct gap for your system. The small kernels simply don't get crushed!

I've seen people leave the brew store with a "double crushed" barley and wheat mix containing lots of uncrushed wheat kernels. Then when they drink it they wonder why the beer is called a wheat.

I totally agree with you there. You really need to know your crush. I have had intermittent luck with my LHBS's crush. One of these days I need to just buckle down and get my own mill.

 

[doug293cz]

I should do a new thread but does anyone have tips on taking samples? I just open the valve on my mash tun but I wonder if readings from the top of bottom make a difference.

My last few brews showed the gravity increasing after 60 minutes so I'm suspect that I'm doing something wrong.

If you are recirculating during the mash, then pulling a sample from the recirc loop should work ok. If you are not recirculating, then pulling a sample from the drain valve will not work very well. The wort in, and near, the drain is in a "dead" spot. Sugar can only get to the wort in the drain by diffusion, and will have a significant delay before the wort there is in equilibrium with the wort in the bulk of the mash. A false bottom in the MLT will make this situation worse. The best way to pull a sample in this case is to open the MLT, give it a good stir, and then pull a sample from under the surface near the top.

Brew on

 

[pretzelb]

If you are recirculating during the mash, then pulling a sample from the recirc loop should work ok. If you are not recirculating, then pulling a sample from the drain valve will not work very well. The wort in, and near, the drain is in a "dead" spot. Sugar can only get to the wort in the drain by diffusion, and will have a significant delay before the wort there is in equilibrium with the wort in the bulk of the mash. A false bottom in the MLT will make this situation worse. The best way to pull a sample in this case is to open the MLT, give it a good stir, and then pull a sample from under the surface near the top.

Brew on

That makes sense. I've avoided doing a stir since my cooler isn't that great at heat retention but I am going to do it next time and take your advice.

 

[brew-bandit]

So here is my plan to turn this almost failure to a success.

Redo the same recipe and method since I know the pre-boil gravity and the OG and will know the FG in a week or two. I will mash exactly the same (full 90 min) but take a refract reading every 15 minutes. This should help determine when the conversion is complete and let you guys know what I find out.

I like the idea of doing 30 minute or less mashes.

 

[RM-MN]

So here is my plan to turn this almost failure to a success.

Redo the same recipe and method since I know the pre-boil gravity and the OG and will know the FG in a week or two. I will mash exactly the same (full 90 min) but take a refract reading every 15 minutes. This should help determine when the conversion is complete and let you guys know what I find out.

I like the idea of doing 30 minute or less mashes.

Change that up and take a refractometer reading every 5 minutes. Be sure to stir the mash because the dense sugars will settle to the bottom.

 

[brew-bandit]

OK I will measure once every 5 min.

If the gravity stops changing significantly in 15-30 min that may have some interesting implications on impact of certain techniques.

Anyone that does BIAB recirculation want to do the same measurements?

 

[TexasWine]

Anyone that does BIAB recirculation want to do the same measurements?

I would, but here's the problem I ran into. To get complete conversion in 30 minutes requires a pretty fine crush. This is exactly what I did for many a BIAB brew day. Set my mill for 0.025 and mashed for 30 minutes. Brewhouse efficiency was great at 83-85%. Everything was good in the land of beer.

Then I upgraded to a recirculating eBIAB. That's when I found out a fine crush and circulating the wort around in a loop doesn't play well together. The wort would not flow through the grain bed and bag fast enough to replenish the pump suction, causing the sump below the basket, where my heating elements are, to go dry. I tried several things to maintain the fine crush and my dearly held 30 minute mashes, but nothing remedied the problem.

I finally loosened the gap on my mill to 0.040, and suddenly my problem was solved. But 30 minute mashes are also gone and have been replaced by 60 minutes. At first this was upsetting to me because I do love an efficient brew day. I even had a few pangs of regret for upgrading my system, because why would I add a piece of equipment that lengthened my brew day? But then I realized two things. One, I was wasting time boiling for an hour. Now I save 30 minutes by reducing my standard boil time to 30 minutes. Two, I did my first multi rest mash this weekend and this set it and forget it approach with recirculating eBIAB was the bee's knees.

Long response to your question, I know. But I thought someone else might be able to glean a thing or two from my experience and hopefully it'll save you some frustration.

EDIT: efficiency is back where it used to be, and hopefully will be there consistently. Consistency and repeatability was a big driver for me to get a recirculating eBIAB.

 

[Mer-man]

Change that up and take a refractometer reading every 5 minutes. Be sure to stir the mash because the dense sugars will settle to the bottom.

This would explain why my mash progress refractometer readings have been low, but my pre-boil reading is on target.
I was freaking out about them being off, and then the OG was fine. *sigh*

Stir, baby, stir.

 

[RM-MN]

I would, but here's the problem I ran into. To get complete conversion in 30 minutes requires a pretty fine crush. This is exactly what I did for many a BIAB brew day. Set my mill for 0.025 and mashed for 30 minutes. Brewhouse efficiency was great at 83-85%. Everything was good in the land of beer.

Then I upgraded to a recirculating eBIAB. That's when I found out a fine crush and circulating the wort around in a loop doesn't play well together. The wort would not flow through the grain bed and bag fast enough to replenish the pump suction, causing the sump below the basket, where my heating elements are, to go dry. I tried several things to maintain the fine crush and my dearly held 30 minute mashes, but nothing remedied the problem.

I finally loosened the gap on my mill to 0.040, and suddenly my problem was solved. But 30 minute mashes are also gone and have been replaced by 60 minutes. At first this was upsetting to me because I do love an efficient brew day. I even had a few pangs of regret for upgrading my system, because why would I add a piece of equipment that lengthened my brew day? But then I realized two things. One, I was wasting time boiling for an hour. Now I save 30 minutes by reducing my standard boil time to 30 minutes. Two, I did my first multi rest mash this weekend and this set it and forget it approach with recirculating eBIAB was the bee's knees.

Long response to your question, I know. But I thought someone else might be able to glean a thing or two from my experience and hopefully it'll save you some frustration.

EDIT: efficiency is back where it used to be, and hopefully will be there consistently. Consistency and repeatability was a big driver for me to get a recirculating eBIAB.

Now I want to hear about flavor. It seemed that when I used a very short mash I had great efficiency but the flavor was muted. It's as if it takes longer to extract the flavors from the caramel or roasted malts that it did for conversion.

 

[TexasWine]

Now I want to hear about flavor. It seemed that when I used a very short mash I had great efficiency but the flavor was muted. It's as if it takes longer to extract the flavors from the caramel or roasted malts that it did for conversion.

Ah ha! I'll let you know. Plan to enter this in the Bluebonnet comp coming up.