• We have a new forum and it needs your help! Homebrewing Deals is a forum to post whatever deals and specials you find that other homebrewers might value! Includes coupon layering, Craigslist finds, eBay finds, Amazon specials, etc.

Fine crush, burnt batch... help troubleshoot

HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.

Help Support Homebrew Talk:

jdudek

Active Member
Joined
Dec 4, 2019
Messages
40
Reaction score
17
Location
Portland
Hello all,

I got myself a mill recently and crushed the grain myself on my last batch. My intention was to improve efficiency. I crushed at 0.025. Crush looked good but there was certainly more flour than ever before.

I put some of the crushed grain dry in my bag, and i could see flour being sifted out. I had nothing to compare that with, i had never tried it with store crush. So made a note of this and moved on.

I brewed as i normally do, w/o much change in any other variables... 13 lbs grain, 7.5 gallon water. mostly Belgian pils, 8 oz of wheat.

I use a bag in a steamer basket
I very gently recirculate for temp distribution
I use an ezboil for temp control
I have 2250W element from BrewHardware.
Single step full volume mash, no mash out, no sparge

I could tell the mash had a lot of particles in suspension outside the bag. Taking samples from drain valve (not from inside the bag), the wort was cloudier than i had ever seen. I removed the basket/bag, squeezed a fair amount ramp to boil (no pump) at 100% and boiled for 1h at 85%. I did crank it up to 95% towards the last i'd say quarter of the boil, as it seemed it could use a bit more power... After draining to fermenter, element is caked in black crud. Took a sample today, it's burnt. Not absolutely awful burnt, but it's there. Still debating whether I will bottle or dump.

As far as i remember the wort tasted fine after the mash.

So... looking for advice. Here are my takeaways

1- Only variable that changed was crush. I've brewed 5 or 6 very successful batches on this setup (albeit of low efficiency) until this last brew.
2- my bag is of some long forgotten origins... probably not a high quality bag.
3- moving the boil power to 95%, maybe a bad move in retrospect
4- somehow, i got a lot more hop trub than i normally do. I use a hop spider so i am not sure how it "escaped" but it did. Perhaps also a burn candidate, though seems less likely.

Thanks for any guidance/advice
 

Jtvann

Well-Known Member
Joined
Jun 4, 2017
Messages
893
Reaction score
286
I just changed my gap down to the same .025, but brewed with rye. I know rye can burn, but wanted to give it a shot. I had the same black burnt element that you had. It was a pain the clean.

I cant say if it's the crush that leads to burning, I've never heard that from anybody else crushing at .025, which plenty of people do. Ill follow up with the next batch I do and see if I have any burning. My element is a 5500 ulwd
 

Genuine

Well-Known Member
Joined
Nov 19, 2011
Messages
920
Reaction score
468
Location
Putnam
Oh dude, you'll be fine. There last time I tried to brew with the wife home, She asked me to do something up stairs....totally forgot about the mash (I use a 2 vessel kettle rims) and my kettle ran dry and element firing for a solid 10 minutes. The basement smelled like an electrical fire, tons of smoke, burnt wort, a burn on my kettle's floor...etc (had to run to lowes to grab a temp element). I lost all hope, however went on with the rest of the brew day. It turned out to be one of the best beers so far and not a single person noticed any sort of burnt flavor or aroma. You'll be fine.
 

LittleRiver

Well-Known Member
Joined
Jul 3, 2017
Messages
1,018
Reaction score
1,145
...my bag is of some long forgotten origins... probably not a high quality bag...
I suspect that is your problem.

With a fine crush you need a bag with a fine weave fabric (swiss voile). Lots of folks on this forum (including me) are very happy with the bags made by Wilser.

I use a mill gap of .025, and get great efficiency without sparging or recirculating. If you recirculate you may have to open the gap up some to get better flow, or add rice hulls. The finer weave of a quality bag is also going to affect recirculation.

Another thing you can try is not recirculating, just insulate the kettle during the mash and you'll be fine. That's what I do. That will also let you get rid of the basket, so more of your water is in contact with the wort.
 
OP
jdudek

jdudek

Active Member
Joined
Dec 4, 2019
Messages
40
Reaction score
17
Location
Portland
I suspect that is your problem.

With a fine crush you need a bag with a fine weave fabric (swiss voile). Lots of folks on this forum (including me) are very happy with the bags made by Wilser.

I use a mill gap of .025, and get great efficiency without sparging or recirculating. If you recirculate you may have to open the gap up some to get better flow, or add rice hulls. The finer weave of a quality bag is also going to affect recirculation.

Another thing you can try is not recirculating, just insulate the kettle during the mash and you'll be fine. That's what I do. That will also let you get rid of the basket, so more of your water is in contact with the wort.
Thanks, that is my suspicion as well. Wilser bag was the next item on the list (i guess it should have been the first!)

I did have a bunch of question about bag/basket/recirc, etc...

if sticking to recirculation
1- if the output port is not directly against the bag but under the basket which holds the bag, will a gentle recirc be ok even with a very fine mesh bag?
2- is it likely that with a thick grain bed of finely crushed malt, recirculation will just send water around the grain in the dead space between the basket and kettle wall rather than through the grain (path of least resistance for liquid basically)

if going bag only no recirc/no basket
1- what's the consensus of keeping a wilser bag directly on element during mash if the element maintains the temperature (single infusion, so steping to higher temps). If there's no recirculation, does that even make sense or does the heat gets concentrated near the element and under the grain bag?
2- what mash efficiency could one expect with a dump and forget of the grain in the bag, full volume, 0.025 crush mostly base malt, and in how much time.

sorry lot to unpack here, I sure appreciate the responses.
 

doug293cz

BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
Lifetime Supporter
Joined
May 14, 2014
Messages
9,900
Reaction score
5,866
Location
Renton
...
2- what mash efficiency could one expect with a dump and forget of the grain in the bag, full volume, 0.025 crush mostly base malt, and in how much time.

...
With a fine crush, you should be able to get 100% conversion of starch to sugar, in which case your mash efficiency will equal your lauter efficiency (mash eff = conv eff * lauter eff.) Lauter efficiency is determined by how much sugar is left in the grain mass after draining the wort. The more sugar/wort left in the grain, the lower the lauter efficiency.

With a traditional MLT, grain absorption will be about 0.12 gal/lb. With BIAB, if you hang the bag for a long time, you can get absorption down around 0.08 - 0.10 gal/lb, and squeezing the bag can get you down below 0.06 gal/lb. Since increasing the amount of grain used increases the amount absorbed by the gain, it also lowers the lauter efficiency.

The following chart shows how lauter efficiency efficiency decreases with increasing grain weight to pre-boil volume ratio, for a variety of batch sparge counts and for two different grain absorption rates. The chart represents an upper limit on your mash efficiency. The lower your conversion efficiency the further below the chart lines your mash efficiency will be.

Efficiency vs Grain to Pre-Boil Ratio for Various Sparge Counts.png


Brew on :mug:
 
OP
jdudek

jdudek

Active Member
Joined
Dec 4, 2019
Messages
40
Reaction score
17
Location
Portland
Thanks Doug, I remember seeing this great chart in another thread, but had forgotten about it! It does answer my efficiency question very nicely. And assuming good pH and constant temp, you reckon that the ~100% conversion efficiency can be obtained solely based on the fine crush? Any thoughts on the time to complete conversion?
 

LittleRiver

Well-Known Member
Joined
Jul 3, 2017
Messages
1,018
Reaction score
1,145
...if sticking to recirculation
1- if the output port is not directly against the bag but under the basket which holds the bag, will a gentle recirc be ok even with a very fine mesh bag?
2- is it likely that with a thick grain bed of finely crushed malt, recirculation will just send water around the grain in the dead space between the basket and kettle wall rather than through the grain (path of least resistance for liquid basically
With a fine crush and a fine weave bag you are asking for recirculation problems, including the one you mention (liquid flowing over the grains rather than through them). Ask yourself why you want to recirculate. It's not needed to get great efficiency, and mash temp can be maintained with insulation. I use a $15 kids sleeping bag to insulate during the mash, and generally maintain temp within 1 degree for an entire hour, and I don't even have to clean up the bag afterward. To me that is way better than messing with a recirculation rig, and cleaning it afterward.

...if going bag only no recirc/no basket
1- what's the consensus of keeping a wilser bag directly on element during mash if the element maintains the temperature (single infusion, so steping to higher temps). If there's no recirculation, does that even make sense or does the heat gets concentrated near the element and under the grain bag?
2- what mash efficiency could one expect with a dump and forget of the grain in the bag, full volume, 0.025 crush mostly base malt, and in how much time.
Whether you can leave the bag in contact with the element depends on the type of element. Some vendors advertise that their ULWD elements will not damage a bag, and there have been some posts where people were successful with that. As you suggest, without recirc it doesn't make sense to use the element to try to maintain mash temps because of heat stratification.

My standard procedure is what you describe in question 2. I crush at .025, don't recirculate, don't sparge, and don't squeeze the bag (it drains over the kettle for the entire boil). I consistently get BH efficiency in the low 80's. I generally mash for 60min, but I've done some 45min mashes with the same results.

Keep in mind that conversion happens very quickly with a fine crush, some have found that it completes in 15min or so (but mash longer than that for flavor).
 
OP
jdudek

jdudek

Active Member
Joined
Dec 4, 2019
Messages
40
Reaction score
17
Location
Portland
Thanks @LittleRiver, that's great info. My recirc setup was for temp control, not really for efficiency. I was hoping to avoid blankets and bungee chords. I don't have a strong argument for that other than a)I like a tidy brew area, b) I'm still in the mess around phase of all this where i open the kettle all the time to take samples or taste or just see whats going on. Having mechanical insulation gets in the way of that and is also undermined by the constant lifting of the lid. My setup has worked great until i decided to go the fine crush route, so it's obviously a trade off. In the end if fine crush and recirc doesn't work, then that is that and ill probably resort to insulating.
 

RM-MN

Supporting Member
HBT Supporter
Joined
Nov 26, 2010
Messages
14,022
Reaction score
4,713
Location
Solway
Thanks @LittleRiver, that's great info. My recirc setup was for temp control, not really for efficiency. I was hoping to avoid blankets and bungee chords. I don't have a strong argument for that other than a)I like a tidy brew area, b) I'm still in the mess around phase of all this where i open the kettle all the time to take samples or taste or just see whats going on. Having mechanical insulation gets in the way of that and is also undermined by the constant lifting of the lid. My setup has worked great until i decided to go the fine crush route, so it's obviously a trade off. In the end if fine crush and recirc doesn't work, then that is that and ill probably resort to insulating.
If you crush fine enough the conversion happens in the first few minutes and temperature dropping after that doesn't matter. Once conversion is complete you are only extraction the sugars and flavor and that can happen at any temp. Try one batch where you just put the bag into the strike water, stir in the grain, and then put the lid on. Check your efficiency at the end of the hour.
 

LittleRiver

Well-Known Member
Joined
Jul 3, 2017
Messages
1,018
Reaction score
1,145
... I was hoping to avoid blankets and bungee chords. I don't have a strong argument for that...I like a tidy brew area... i open the kettle all the time ...
If you're having fun with your rig, you're doing it right. There's a lot of different ways to achieve the same result.

Regarding a tidy brew area, I agree with you, except that I find my kids sleeping bag to be a more tidy and elegant solution than pump, tubing, and wiring. I never have a need to open the kettle during the mash, but it's super easy to do, just open the zipper.

IMG_20190116_094930_282.jpgIMG_20190116_095300_337.jpgIMG_20190116_100512_658.jpg
 

Hwk-I-St8

Supporting Member
HBT Supporter
Joined
Jan 10, 2014
Messages
1,744
Reaction score
732
Location
The Hawkeye State
If you crush fine enough the conversion happens in the first few minutes and temperature dropping after that doesn't matter. Once conversion is complete you are only extraction the sugars and flavor and that can happen at any temp. Try one batch where you just put the bag into the strike water, stir in the grain, and then put the lid on. Check your efficiency at the end of the hour.
I don't know that that's entirely true. Let's say you want to mash at 157 to leave more complex sugars and produce a higher final gravity (some I do with stouts because I don't like dry stouts, I like 'em a bit sweet with a thick mouthfeel). If your temp drops down to 150, you'll get more beta amylase action and break down a lot of those more complex sugars, producing a more fermentable wort than you intended. It's not just about getting the sugars out of the grains, it's also about breaking them down into something the yeast can consume (or not, if that's your intention).
 

RM-MN

Supporting Member
HBT Supporter
Joined
Nov 26, 2010
Messages
14,022
Reaction score
4,713
Location
Solway
Beta amylase denatures quickly at mash temperatures. Estimates are that it survives less than 5 minutes.
 

Jayjay1976

Bubblegazer
Joined
Nov 26, 2016
Messages
3,070
Reaction score
2,302
Location
Chicago
Get a roll of reflectix and make a 3-4 layer jacket for your kettle. Mine is three pieces of reflectix wrapped around the kettle and pinched together with binder clamps in the back to keep it in place. If I splash wort on it I can remove it in just a few seconds. I recently took it off for a cleaning and didn't bother putting it back again; when I brewed a batch without it the temp fell close to 9 degrees in an hour vs. the typical ~4 I usually see with the jacket. I also don't like the thought of blankets, sleeping bags, etc. in my brewing space, the reflectix is much neater, plus it looks like NASA insulation which is cool.

About the scorching, I run an almost identical setup to OP's and have burnt a few batches. Upgrading to a Wilser bag and opening up my mill gap to credit card thickness solved that problem as well as eliminating a nasty bitter husk flavor that haunted many of my beers.
 
Last edited:
OP
jdudek

jdudek

Active Member
Joined
Dec 4, 2019
Messages
40
Reaction score
17
Location
Portland
About the scorching, I run an almost identical setup to OP's and have burnt a few batches. Upgrading to a Wilser bag and opening up my mill gap to credit card thickness solved that problem as well as eliminating a nasty bitter husk flavor that haunted many of my beers.
Thanks for the reply @Jayjay1976 , do you know what kind of efficiency you are getting with your credit card size crush? I assume that is about 0.03 (that's what google says the thickness of a credit card is...)
 

Jayjay1976

Bubblegazer
Joined
Nov 26, 2016
Messages
3,070
Reaction score
2,302
Location
Chicago
The switch to a coarser crush actually increased my efficiency from ~74% to a solid, predictable 77%.
I can't explain that but the first several batches were consistently above expected OG; tweaking the efficiency in brewersfriend until all the numbers line up put it at 77%. Another potential factor might be the switch to lower watt density heating elements. I would guess that reducing the element surface temps means less denatured enzymes? I dunno, but your question was about what kind of efficiency you can expect with a coarser crush and a finer mesh bag. You might lose a few points but hey, no more scorched beer is definitely worth it. Base malt is cheap.
 
Top