Any ideas why my mash efficiency was so low?

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Facticity

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Hello all,

Just finished brewing a rye saison this morning. Grain bill was:

3.5kg Maris Otter
1kg Rye malt
.5kg Wheat malt

I did a single infusion, thickness 3L/kg, at 64*C for 75 min in a BIAB cooler mash tun. I then squeeze the bag, and single batch sparge in my kettle with the remainder of the needed water at 75*C for 5 mins. I squeeze the bag, discard grains, then transfer over wort from the mash tun and mix.

Beersmith predicted pre-boil of 1.039. Hydrometer gave me 1.022 at the calibrated temp.

I hit all my temperatures within half a degree, the mash itself went perfectly. All I can think of is overly coarse crush? I have had troubles getting a consistent crush with my new roller mill, the dials are set to .05 and I believe this time it came out with very few whole grains and a good deal of flour (which i'm okay with since i'm using a bag). Is there anything else that could influence this result? Maybe the issue is the rye not extracting properly?

Let me know what you think.

UPDATE: OG ended up being 1.052, only 2 points off the predicted 1.054. Note there was a 100g sucrose addition in the boil (accounted for by beersmith). The boil off was only .5L less than predicted.

So I have no need to panic... still, why the low post-mash reading??
 
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Hammy71

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I typically get a lower conversion with ryes and wheats. I compensate by guestimating some extra when I mash. Nothing scientific, just experience with my system.
 

wilserbrewer

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Your gravities of 1.022 vs 1.039 and an OG of 1.052 indicates a gross error in your preboil gravity. What temp was your sample?

Correcting for temp can be inaccurate, did you subtract points rather than add points?

Rather than taking gravity with a hot sample, keep a large coffee cup or small metal pot in the freezer to hold and cool your hot samples prior to taking gravity. Also then place your hydrometer w preboil gravity sample in the cup and let it cool to ambient during the boil and recheck.

There’s an error somewhere???

Ideally rye and wheat would be crushed separately at a much tighter gap as they are small and very hard.

I’ve read some have good results using a burr type mill aka corona mill on rye and wheat as this will really crush the crap out of it compared to a roller mill, giving the kernels the thorough punishment they need :)

Might help to run the rye and wheat through the mill on their own and have a look, then combine and run the entire grain bill through the mill again, so mulling the rye and wheat 2x, and the barley 1x. Just an idea.
 
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Saboral

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Probably because you’re using metric :mug:

At 3L/kg I think I’m coming up with about 1.44 qts/gallon which is pretty good. I generally shoot for something slightly thinner.

You didn’t mention an initial stirring or agitation of the mash upon dough in. You could have dead spots in the mash that have dough balls without stirring. I know without an initial stir may efficiency will drop.

Also are you stirring and vorlaufing when you go to do your sparge?

Oh and based on the update, temperature has a big effect on your hydrometer readings try cooling your sample to room temperature and then test.
 

dmtaylor

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It's the crush. Rye and wheat kernels are smaller than barley. That being said, I crush every batch with the same mill gap setting and never have a problem. Find the gap setting where you can just barely crack the rye into a few bits. Then use that setting for everything forever.
 

Morrey

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Several factors can come into play and several have already been discussed above:

Wheat and Rye are harder, husk-less grains and benefit from a separate crush from your barley malts. When I grind mine together on my standard barley gap setting, I'll always be low in efficiency. Wilser mentioned this, and I grind my wheat/rye with a Corona burr mill separately from a roller mill for the barley.

Check your mash Ph. This factor may have some impact but typically not as much as grind. Still is worth checking for maximum efficiency.

Stir the wort very, very well after removing your grain bag and squeezing/draining. The wort tends to form layers, and if not stirred vigorously after lautering, inaccurate readings may occur.
 
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doug293cz

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Since your OG was close to predicted, your pre-boil gravity measurement is surely in error (as Wilser pointed out.) I suspect your pre-boil gravity reading was so low because of inadequate mixing of the first runnings and sparged wort. Your gravity sample likely came from a region richer in sparged (lower gravity) wort. It really takes quite a lot of mixing to really homogenize two different concentration worts. A quick stir will not be adequate.

The fact that your OG was slightly under target may be due to inadequate crush of the wheat and rye, as others have pointed out. Or, it may be due to having a slightly higher post-boil volume than intended.

Brew on :mug:
 

mabrungard

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Mill is set to 0.05, but what units? If its inches, then that is a pretty coarse crush. I typically see 0.04" to 0.03" reported by most homebrewers. I use 0.036" and I condition my grain before crushing with a very light water spray to soften the husks.
 
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Don't be afraid to mash longer as well. Although you went 75 minutes, many BIAB devotees recommend 90. The more chance the grain has to become fully saturated, the more likely sugars will be extracted.
 

mabrungard

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There is nothing wrong with that, and don't let anyone tell you different!
Dave, I have to disagree with you. Every cell of the husk material that is broken open, increases the potential for tannin and silicate to move from those husks into the wort. Better beer will always be made with properly crushed malt. If pulverizing malt and husk into flour actually made better beer, the pro's would already be doing it.
 

dmtaylor

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Dave, I have to disagree with you. Every cell of the husk material that is broken open, increases the potential for tannin and silicate to move from those husks into the wort. Better beer will always be made with properly crushed malt. If pulverizing malt and husk into flour actually made better beer, the pro's would already be doing it.
And my experience says it's not as bad as you think. Clarification, though: I didn't pulverize to flour. I quit pulsing when the kernels were broken into about 6 pieces on average. So you may indeed have a point for those pulverizing all the way down to flour.
 
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HopHeavy

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@Facticity reports that he came within two points of his estimated starting gravity. The crush couldn't have had that great of an impact. He couldn't "make up" for such a great loss of efficiency.

still, why the low post-mash reading??
I think you may have answered this, at least partially, earlier in your initial post. My Beersmith calculates sugar additions as malts. So I determine my estimated preboil gravity BEFORE I add sugar to the recipe.

Regardless of where your discrepancy came from, you got some sound advice concerning mill gap and dilution methods. Put it all together and you will very likely eliminate the issue for future brews.
 

C-Rider

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Dave, I have to disagree with you. Every cell of the husk material that is broken open, increases the potential for tannin and silicate to move from those husks into the wort. Better beer will always be made with properly crushed malt. If pulverizing malt and husk into flour actually made better beer, the pro's would already be doing it.
Never had any of those problems from any judges in various contacts here in the islands. I'll go look for a picture of my "crush".
 

mabrungard

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I was just reading through the Malt book and the chapter on milling. Way back when, malt milling was done between two rotating stone discs similar to flour mills. Something like one or two hundred years ago, brewers devised the roller mills. The author, John Mallet, did make the same admission that I made above: The more you pulverize and break open those cells in the husk layer, the greater the opportunity to introduce tannins. He failed to mention silicates, but I know that they are in the husk too.
 

dmtaylor

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I wonder how many 21st century brewers have used pulverized grain to know the effects first-hand, versus how many parrot something as fact that they don't actually know for a fact. This question applies to Mallet or to anyone else. I dare anyone to answer it based on actual experience.
 

Lefou

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Personally, I would see no real issue with pulverizing portions of wheat grain grist to near flour consistency for two reasons.

One, the wheat malt has no hull and generally higher diastatic enzyme content
Two, pulverizing the wheat into smaller fragments could speed gelatinization and conversion. As long as the amount of wheat pulverized in such a manner didn't interfere with proper lautering and cause a sticky sparge, why not try it to boost conversion efficiency?
I've done this and with an extended mash, it's worked out well in certain styles.

Have I done this with exclusively barley malt grist? Nope.
 

Lefou

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To anyone considering experimentation with pulverized grain, be sure to account for a big gain in efficiency. Probably about 10%, or maybe more if your previous crush was not awesome.

This happened on my last brew.
I went from 68% to almost 80% by extending the mash time and grinding the malted wheat portion down really well. The barley portion was well-ground Pilsner malt.
 

kh54s10

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I use a Corona style mill. I do not mill to flour but the mill pretty much shreds the hulls. I have never tasted tannin, I think. I like most of my home brews better than the average craft beer.

Maybe it is that I like tannin?? o_O
 

Lefou

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According to Chris Colby, there's going to be some tannin in beer, no matter what ... but there are some hints to reducing tannin. I read his blog regularly and took a few of those hints to heart.
One of them is getting a good "hot break", using calcium salts properly, and adding a Whirlfloc to beers I'd like to clarify to some degree.
 

Morrey

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Mill is set to 0.05, but what units? If its inches, then that is a pretty coarse crush. I typically see 0.04" to 0.03" reported by most homebrewers. I use 0.036" and I condition my grain before crushing with a very light water spray to soften the husks.
Martin, I set my MM3 at .035 for barley so we are on the same page here. I use a Corona burr mill to grind wheat and rye separately and the grind seems finer than with the MM3. There are no husks to be concerned with on wheat and rye which {may} cause tannin issues, but I have never had tannin issues that I could detect.

Don't be afraid to mash longer as well. Although you went 75 minutes, many BIAB devotees recommend 90. The more chance the grain has to become fully saturated, the more likely sugars will be extracted.
About a year ago I increased from 60 min mashes to 75 minute mashes. My beers seem more flavorful today than back then, and I assume a longer mash is at least part of the total reason. My mash efficiency has remained nicely stable whether at 60 minutes or 75 minutes, but the flavor seems richer at 75.

I use a Corona style mill. I do not mill to flour but the mill pretty much shreds the hulls. I have never tasted tannin, I think. I like most of my home brews better than the average craft beer.

Maybe it is that I like tannin?? o_O
Maybe I like tannin too, but I don't think I have ever had that issue either. Makes me wonder what some folks are doing to ruin a beer with tannins and astringency.

According to Chris Colby, there's going to be some tannin in beer, no matter what ... but there are some hints to reducing tannin. I read his blog regularly and took a few of those hints to heart.
One of them is getting a good "hot break", using calcium salts properly, and adding a Whirlfloc to beers I'd like to clarify to some degree.
Since these are some of the things I routinely do, its possible I am reducing tannins to the non-detectable level. As mentioned to kh54s10 above, I really don't know how harsh tannins get into a beer to begin with. Inquiring minds would like to know.
 
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