Mash debate

[capt82]

I just had my worst efficiency (59%) and attenuation (59%). I am debating to what the most likely cause was.

1) It was the first time I ordered my grains and dry Nottingham yeast online. I was a little suspicious about the grains being crushed at the right setting because I saw none of the usual powder at the bottom of the bag. Could the yeast been subjected to high heat during shipping? The best use by date was about 2/2023 so they were not old.
or
2) About 22% of my grain bill were flaked oats and flaked corn. I mashed at 150* for 90 minutes. Do these adjunct require longer mash times? These were the most flakes I have used in any of my beers.

I realize it's probably all of the above. Just trying to narrow it down..

 

[bracconiere]

well to convert to my effec, i'd have to know how many pounds total, and how many gallons into fermenter....and what OG, FG....

edit: oh and how long and how did you sparge? or is this BIAB?

 

[RM-MN]

Mash efficiency is usually directly related to the quality of the crush. I think you are on the right track when you mentioned the lack of powder.

 

[jdauria]

Most homebrew shops, even online ones, crush the grain at fairly wide gap to prevent customers from getting stuck mashes using tradition mash tun/brew kettle systems. If you are brewing in a bag, or using say a electric system with a malt pipe, you want a finer crush. Also 22% of flaked adjuncts will effect efficiency too. Were they crushed also? Flaked grains can cause a gummy mash and wort will not drain well, you need to add rice hulls, like 0.5 to 1 lb (for 5 gallon batch) to mash when using flaked grains or wheat and rye to help the mash drain better.

 

[AlexKay]

Plus-plus on crush. Was this your first time ordering from this particular vendor? What really pushed me to get a grain mill was my efficiency would bounce all over the place depending on who was milling my grain for me.

I don't think adjuncts are your problem. I've had up to 50% (hello, witbier) without problems provided there's enough diastatic oomph in the rest of the grist. And my feeling is that yeast (dry yeast particularly) is more of an all-or-nothing affair: you wouldn't get a sort-of-attenuated beer; it would either be fine or a disaster.

How are you measuring your gravities?

 

[IslandLizard]

Did you measure your beer FG with a refractometer perhaps? If so, that will skew the gravity unless you apply a correction formula to count for alcohol being present.

 

[capt82]

well to convert to my effec, i'd have to know how many pounds total, and how many gallons into fermenter....and what OG, FG....

edit: oh and how long and how did you sparge? or is this BIAB?

13 lbs of 2-row, 3.6 lbs of flacked corn and oats, 6.5 gal into fermenter, 1.055 OG, 1.023 FG... NBo BIAB. I sparge for at least 30 min.

Thnx

 

[capt82]

Did you measure your beer FG with a refractometer perhaps? If so, that will skew the gravity unless you apply a correction formula to count for alcohol being present.

No. I used my $10 hydrometer as I always have.

 

[capt82]

Most homebrew shops, even online ones, crush the grain at fairly wide gap to prevent customers from getting stuck mashes using tradition mash tun/brew kettle systems. If you are brewing in a bag, or using say a electric system with a malt pipe, you want a finer crush. Also 22% of flaked adjuncts will effect efficiency too. Were they crushed also? Flaked grains can cause a gummy mash and wort will not drain well, you need to add rice hulls, like 0.5 to 1 lb (for 5 gallon batch) to mash when using flaked grains or wheat and rye to help the mash drain better.

The flakes were not crushed with the 2-row. I also had a very clean mash drain compared to my usual fight to filter out the grist.

 

[Dland]

I always run my flaked grains through crusher too, seems to help with their conversion during mash. Never had problems w stuck mash in doing so, only time I use rice hulls is with rye.

 

[bracconiere]

NBo BIAB. I sparge for at least 30 min.

i'm not sure what that means? but yeah, that's crap effec...what was your strike temp, and did you check the temp after adding grain? and is the thermometer accurate?

and 30 min isn't really a long enough sparge if that was a typo for No BIAB....

and that's a pretty big grain bill for a 6.5 gallon batch? how big is your mash tun? and how much boil off did you have? that's about how much grain i use for a 10 gallon batch, for a og of 1.060?

low effec is common for BIG batches....if you got something decent effec wise, it would have been like pushing 1.080. which in my head is a BIG beer, hard to really get good effec...

 

[IslandLizard]

No. I used my $10 hydrometer as I always have.

Ah, good!
How sure are you your mash temp was accurate? Low mash or brewhouse efficiency can be due to many factors, such as milling, diastatic power, mash temps, sparging methods, etc.

But lower attenuation than expected is typically due to (higher) mash temps or poor yeast health and pitch rate.

Flaked oats, wheat, rye, etc. are generally sufficiently pregelatinized.
However, depending on how it was processed, flaked corn may benefit from a cereal mash or a 20' boil before mashing it. That (thin) corn soup/polenta then becomes your strike water, after adjusting for volume and temp.

 

[bracconiere]

I currently use a hose from my HLT to the top of my mash tun where I have a 1/2" pvc pipe that goes through the lid of the mash tun. The pipe then tee's to several horizontal pipes with drilled holes in it. I control the flow from the HLT and it seems to drip evenly over the gain bed.

I saw this on Amazon and it seems to be an easy sparge diffuser.

so you do fly sparge...did you check the temp after a while? a hole cut in the lid sounds like you might lose a lot of heat during the mash? you said 90 minutes?

 

[hotbeer]

You said your running's were clearer than normal. That might be expected if the crush is coarser. But also might be an indication that your water formed channels in the mash and missing most of the grain.

Your FG being so high might be poor control of mash temps and you got more unfermentable sugar. Not sure if crush size will have a big effect for that or not.

I wouldn't expect the dry yeast to suffer any brief times the package was exposed to high ambient temps during shipment. So put that out of your mind unless you know for certain it sat in 140°F temps for 12 or so hours. (yes I pulled that number out of my ...) It takes a while for the contents of the box to match the ambient temps.

 

[bracconiere]

oh not to sound like the guy asking if you plugged it in, but....

the sample you tested to get 1.055 wasn't 150f hot was it?

edit: and you said you used your hydro, but do you have a refrac also? i'd be curious to compare the two readings against each other on the final beer?

 

[capt82]

i'm not sure what that means? but yeah, that's crap effec...what was your strike temp, and did you check the temp after adding grain? and is the thermometer accurate?

and 30 min isn't really a long enough sparge if that was a typo for No BIAB....

and that's a pretty big grain bill for a 6.5 gallon batch? how big is your mash tun? and how much boil off did you have? that's about how much grain i use for a 10 gallon batch, for a og of 1.060?

low effec is common for BIG batches....if you got something decent effec wise, it would have been like pushing 1.080. which in my head is a BIG beer, hard to really get good effec...

I always plan for a 70% efficiency and usually get about 75%. Based on Brewers Friend, I should have got an OG of 1.065 and FG of 1.015. I used Nottingham Ale Yeast and the apparent attenuation given by BF is only 77%.

But now you have me thinking... I didn't weigh the grains that AIH sent me. Maybe I did not get the 13lbs of two row I ordered.

 

[bracconiere]

But now you have me thinking... I didn't weigh the grains that AIH sent me. Maybe I did not get the 13lbs of two row I ordered.

that wouldn't explain the high FG...i still am thinking 30 mins for a fly sparge is too quick...

edit: and have you checked the hydro in water recently? not that would explain the low, AND high readings.....

 

[capt82]

oh not to sound like the guy asking if you plugged it in, but....

the sample you tested to get 1.055 wasn't 150f hot was it?

edit: and you said you used your hydro, but do you have a refrac also? i'd be curious to compare the two readings against each other on the final beer?

No, but good thought. It was 70*f.

 

[capt82]

You said your running's were clearer than normal. That might be expected if the crush is coarser. But also might be an indication that your water formed channels in the mash and missing most of the grain.

Your FG being so high might be poor control of mash temps and you got more unfermentable sugar. Not sure if crush size will have a big effect for that or not.

I wouldn't expect the dry yeast to suffer any brief times the package was exposed to high ambient temps during shipment. So put that out of your mind unless you know for certain it sat in 140°F temps for 12 or so hours. (yes I pulled that number out of my ...) It takes a while for the contents of the box to match the ambient temps.

I try for 153*f and this time ended up at 150*f due to my cold brew day. I've had several 148*-150* mashes before and never have an issue.

 

[bracconiere]

No, but good thought. It was 70*f.

LOL, ok just thought i'd ask! never sure who you're talking too....

how big is your mash tun again? and what type?

 

[tracer bullet]

Off the top, and it's already been said...

OG ~ grain crush
FG ~ unhappy yeast

That's where I'd change things / try to improve the next time.

 

[capt82]

LOL, ok just thought i'd ask! never sure who you're talking too....

how big is your mash tun again? and what type?

10 gal igloo. Holds temp perfect.

 

[bracconiere]

10 gal igloo. Holds temp perfect.

ok, qts/lb ratio?

 

[capt82]

ok, qts/lb ratio?

1.30 qts/lb

 

[bracconiere]

so you sparged with about 4 gallons? wish i could go back in time, and ask what the final runnings were coming out of the mash tun at...

 

[capt82]

so you sparged with about 4 gallons? wish i could go back in time, and ask what the final runnings were coming out of the mash tun at...

4.6 gallons. I am pretty consistent with hitting my target OG so I never thought to check it before ending the boil. I could have added some sugar or boiled it down longer if I new.

 

[bracconiere]

4.6 gallons. I am pretty consistent with hitting my target OG so I never thought to check it before ending the boil. I could have added some sugar or boiled it down longer if I new.

now that i have a spiffy digital refrac, i like checking the runoff from the mash tun as it's running off....being i just need a couple drops and not a whole cylinder, and have to temp correct it on top of that....

i had a crap batch, and i knew i was rushing the sparge because, the runnings at the end were still like 1.024 or so.....but i said f it...in goes the cheap/cheat

 

[rhorwitz]

Getting back to the crush size. I use my own grain crusher and have it set on the fine side. Yes, I do get a stuck mash, but with some rice hulls it makes it tolerable. I have to fight to unstick the mash, but after the first sparge, it's downhill. I'm getting such a great a efficiency, BH of 84% according to beersmith. Last, I have roused dead WLP 001 yeast back to life (1-1/2 years old) and it works fine. survival of the fittest.

 

[IslandLizard]

Getting back to the crush size. I use my own grain crusher and have it set on the fine side. Yes, I do get a stuck mash, but with some rice hulls it makes it tolerable. I have to fight to unstick the mash, but after the first sparge, it's downhill. I'm getting such a great a efficiency, BH of 84% according to beersmith. Last, I have roused dead WLP 001 yeast back to life (1-1/2 years old) and it works fine. survival of the fittest.

Can you elaborate on the gap width and mill you're using?
What kind of mash tun and sparge method? Using a false bottom or something else?

What do you mean with the mash gets "stuck?" It's difficult to lauter?

I'm getting a similar mash efficiency (82-84% on 1.060-1.065 OG mashes). I only run into lauter problems when using larger %s of wheat or rye (above 20-30%) without using a beta-glucanase/protein rest at 121F for 15'. I batch sparge, twice, which makes everything quite simple.

 

[MicroMickey]

Mash efficiency IS NOT mainly dependent on crush. I really don't know where this idea comes from. The principal factors are temperature, water to grist ratio, pH, and time. Everyone seems to look for a silver bullet which will make all of their problems disappear. I haven't found it either.

 

[tracer bullet]

Mash efficiency IS NOT mainly dependent on crush.

I'd agree there are many factors. I'd also say that, in my experience, when folks have issues and ask the forum about it, crush is the culprit far more often than not. Most folks are in the ballpark for temps, most mash for at least an hour, and I've had some of my own pH mishaps that had surprisingly little effect. Water to grist ratio is an issue for the electric units with an inner pipe for the grains at times, a lot of dead space can be found under and around them, but that doesn't seem to be the case here.

Don't get me wrong, I'll again agree there are many factors. My experience has been that issues folks have are affected by the crush much more often than not. Just my experience / opinion of course.

 

[VikeMan]

Mash efficiency IS NOT mainly dependent on crush.

It's very often found to be the culprit. There are literally thousands of "case studies" on the forums, where improving the crush fixed efficiency.

The principal factors are temperature, water to grist ratio, pH, and time.

These are also important, particlularly when they are very far away from ideal value ranges. Not to mention dead space and transfer losses (if applicable), and even diastatic power if the DP is really low. And/but I think it's silly to name any one of the factors and call it the "main" factor (or not the main factor). When someone is having an efficiency problem, the "main" factor that needs to be addressed is whichever one (or more) that's causing the problem.

 

[CascadesBrewer]

Mash efficiency IS NOT mainly dependent on crush. I really don't know where this idea comes from. The principal factors are temperature, water to grist ratio, pH, and time. Everyone seems to look for a silver bullet which will make all of their problems disappear. I haven't found it either.

There is just a lot of real world experience that points at grain crush as being a huge driver in efficiency. Maybe this is more true with BIAB, but I also experienced swings in efficiency back when I used to fly sparge and did not have my own mill. My girlfriend saw around 10% boost moving from getting grain crushed at the local store vs me milling it for her.

I would say that grain crush has a much larger impact than any of the other factors you list. Yeah, you probably cannot get by with a oatmeal thick mash at 140F for 15 minutes at a 4.2 pH, but most of these factors have fairly wide ranges. If you are using a sparge process, your process can have a big impact. Also, a system that leave behind wort will significantly lower efficiency.

 

[rhorwitz]

Can you elaborate on the gap width and mill you're using?
What kind of mash tun and sparge method? Using a false bottom or something else?

What do you mean with the mash gets "stuck?" It's difficult to lauter?

I'm getting a similar mash efficiency (82-84% on 1.060-1.065 OG mashes). I only run into lauter problems when using larger %s of wheat or rye (above 20-30%) without using a beta-glucanase/protein rest at 121F for 15'. I batch sparge, twice, which makes everything quite simple.

Yes, first let me preface that I am curious myself why my efficiency is so high, but it precisely consistent which is my first and foremost objective. My grain mill is a economy grade "Barley Crusher" by MaltMill. I have a ~.7 mm gap on my rollers. My mashtun is a simple 15/20 gallon Igloo with a false screen bottom. On the lid I fashioned a banjo style lawn sprinkler (I picked up for a couple bucks). I have a hot liquor tank that gravity feeds the hot water to the mash though the lawn sprinkler. However, I recently started feeding the hot water through the bottom so that the mash does not have any pockets of air. I normally use 165-170 deg F this will reduce in temperature, as the grain will offset the heat (strike temp) to ~155-160. I fill about 50 mm above the grain. Using my paddle I mix to ensure no dry pockets. I add more water as needed maintaining 50mm of water over the grain. I let is set for 15 minutes. After, I turn on my recirculating pump on for 5 minutes or until it starts to cavitate, as the wort from the mash gets stuck and does not collect at the false bottom. I do this 3 to 4 times during the 1:20 mash. After, I switch my pump to dump into my brew kettle while allowing fresh hot water (170) to sparge. This is done in batches at first, as the mash gets stuck. So I fill the mashtun at least 100mm above the grain line and using my paddle I mix until the mash is unstuck, I turn on my pump and and drain into brew kettle. I repeat this process until I get the desired amount of wort.
Pious brewers will note that I am breaking a lot of rules here. To add more outrage, I never check my pH. The end product is a very high conversion efficiency, so high that the spent grains have little nutritional value, the deer and other critters leave it alone.

 

[eric19312]

I'm sure crush is part of the story here but there is different set of facts than normally seen when we normally get a "why is my efficiency so low thread?".

The poor attenuation issue needs consideration. Out on a limb here but my thinking is crush has little or nothing to do with poor attenuation. If this was liquid yeast I might suspect the yeast was handled badly but it is dry yeast, and it did ferment, just not to the extent it should have. Nottingham is characterized as a high attenuating yeast with many users reporting mid 80s into 90s. 59% attenuation with FG 1.023 FG....

Somehow you ended up with not enough sugar in the kettle, and what did get in there was not very fermentable. I'd check calibration on your thermometers and hydrometer. Perhaps a starch test would be worth adding to your troubleshooting also.

 

[MicroMickey]

Somehow you ended up with not enough sugar in the kettle, and what did get in there was not very fermentable.
[/QUOTE]

Somehow you ended up with the wrong balance of sugar in the kettle. The major purpose of mashing is to degrade proteins, gums, and starches in the grain to produce a wort which will suit our purposes as brewers. "To avoid going through all the trouble of doing it right, I'll just grind the malt into flour." That statement might sound facetious but it's closer to the truth that most of us would like to believe. Different beer styles require a wort of specific properties. Some beers are supposed to be thick, malty, and sustaining while others should be thinner, crisp, and refreshing. The method of mashing you employ will determine the kind of beer you produce.

If you're not getting what you want in the kettle or fermenter, stop and really think about what you're doing. There really isn't a good alternative to doing things right.

 

[ScrewyBrewer]

In my experience, when the final gravity measures higher than expected, I look for poorly attenuating yeast or having too many unfermentable sugars in the wort as the root cause. In recent memory, I find Windsor yeast delivers lower attenuation consistently, and a mash temperature would need to be a lot higher than 155F/68.3C to produce enough unfermentable sugars in the wort.

 

[CascadesBrewer]

Somehow you ended up with not enough sugar in the kettle, and what did get in there was not very fermentable. I'd check calibration on your thermometers and hydrometer. Perhaps a starch test would be worth adding to your troubleshooting also.

Yeah, I was wondering how the two could be related. I once mashed my Porter at 162F by mistake due to an out of whack thermometer. A friend recently mistook 85% acid for 10%, and mashed at a crazy low pH. In both cases, mine and his, the OG and efficiency seemed normal but attenuation was terrible. I am not positive if there is a single factor that would drive both low OG and low attenuation (well, maybe mashing at 130F) but I agree about the calibration recommendation.

 

[TheMadKing]

I saw the thread title and thought to myself... hey I am really good at Mash-Debating!

totally not what the thread is about

 

[TheMadKing]

Yeah, I was wondering how the two could be related. I once mashed my Porter at 162F by mistake due to an out of whack thermometer. A friend recently mistook 85% acid for 10%, and mashed at a crazy low pH. In both cases, mine and his, the OG and efficiency seemed normal but attenuation was terrible. I am not positive if there is a single factor that would drive both low OG and low attenuation (well, maybe mashing at 130F) but I agree about the calibration recommendation.

To contribute something possibly useful instead of my bad puns...

not stirring the mash well (i.e. dough balls) could have caused both issues as well.

Less grain being hydrated results in poor extraction and low efficiency

Then during sparging the dough balls get rinsed so a bunch of unconverted starch winds up in the wort hurting fermentability as well