Mash debate

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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.
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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

 

[Bobby_M]

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.

While your statement contains some truth, it's not the most helpful way to say it. Grind isn't the end all but it certainly has a measurable impact on the speed of conversion and the allowable speed of sparging. In case that's not clear, a coarse crush takes longer to convert because it takes long to hydrate. A coarse crush requires a slower fly sparge because diffusion out of the core of larger particles just takes longer. We can debate a bit about how much of the overall conversion picture is impacted by crush, but it would be absolutely false to say that it doesn't matter.

Also, silver bullet? When I read the thread it looks like a bunch of people trying to be helpful and brainstorm all the reasons why efficiency may be low.

Temp
Time
Crush
pH
Total Diastatic Power

Those all factor in to conversion and many of them are interdependent. To troubleshoot conversion, you have to measure wort gravity directly out of the mash before sparging.

Once you collect all your wort in the kettle you can measure lauter efficiency.

Finally when the wort is in the fermenter, you can measure brewhouse efficiency.

In my opinion, the low efficiency was likely a combination of many factors. At 150F, a slight mis-calibration of the thermometer reading high would slow conversion down quite a bit. If the grain crush was coarse, it would be even worse. Couple that with a relatively low diastatic power of the total mash with the higher percentage of adjunct, I'm not surprised. Without measuring gravity in the mash directly, we can't separate out conversion and lauter technique effects.

 

[bracconiere]

Those all factor in to conversion and many of them are interdependent. To troubleshoot conversion, you have to measure wort gravity directly out of the mash before sparging.

Once you collect all your wort in the kettle you can measure lauter efficiency.

Finally when the wort is in the fermenter, you can measure brewhouse efficiency.

you know for some reason i've never had ALL the diferent effecs explained to me to where i could understand, but knew it was pin pointing losses....if i could book mark that i would...and i plan on checking first runnings against pre-boil from now on for i guess conversion effec, lauter, and all that!


finally a simple enough explanation i could understand!