Horrible extraction efficiency

[GRJBowers]

So I brewed a version of BierMuncher's Ode to Arthur Guiness clone, modified to be a partial mash. The actual mash bill was:

3 lb pale 2-row
2 lb toasted barley flakes
1 lb Roasted Barley

Mashed for 1 hour at 154°F and got a paltry 55% Extract efficiency

I used Bru'n Water to predict a mash ph of 5.2 using the Wicklow Mountain water profile (built the water with RO + salts). I didn't have a ph meter at the time so I can't verify whether I was in the ph ballpark or not. I've made an imperial stout that used 2 lbs of roasted grains and got 88% extract efficiency, so I question whether or not they are the culprit. However, I've also made an oatmeal stout where I used only a pound of flaked oats and got a 71% extract efficiency. This makes me think that the flaked barley might be responsible.

It's my understanding that flaked adjuncts are pre-gelatinized and don't require any special preparation or milling. Am I wrong about that? Would a longer mash time have helped? Or does it have nothing to do with the adjuncts and more to do with the water?

I'd appreciate any input.

 

[doug293cz]

Do you mill your own grain? If not, and you buy grain from multiple sources, you could be getting very different levels of crush. The most important factor for conversion efficiency is the degree of crush. Coarse grits don't convert as fast or completely as fine grits. Different crushes could go a long way towards explaining the wildly different efficiencies you have seen.

Brew on

 

[Talgrath]

So a couple of things jump out, for starters, that's an awfully low amount of base malt, generally base malts should be at least 70% of your beer by gravity points. That's also an awfully high amount of flakes vs malts, I have to wonder if that might interfere with your efficiency; I typically don't use more than a pound of flakes in a beer and that's with a higher grain weight by at least a couple of pounds. Beyond those potential issues, how much water are you using? The thickness or thinness of your mash can have a big effect on your efficiency. Is this brew in a bag? If it's a more traditional mash, are you sparging? If so, batch sparge or fly sparge?

 

[specharka]

The unmalted barley is the culprit here. Flaked and roasted grains contribute zero diastatic power to the grist and will result in poor mash efficiency when used in abundance (>30%). Typically base 2-row malt has enough diastatic power to convert itself and its weight in other starches to polysaccharides, but throw in any number of factors (mash thickness, pH, time and temperature) and you might as well cut it in half.

And while the flaked grains do come pregelatinized, the absence of a husk will produce a viscous wort that can make conversion an arduous detail and lautering a nightmare. A mash out step can really improve efficiency for extremely viscous worts. For what it’s worth, I recently brewed a black IPA with 18% flaked barley and roasted malt and experienced these issues firsthand.

 

[GRJBowers]

Do you mill your own grain? If not, and you buy grain from multiple sources, you could be getting very different levels of crush. The most important factor for conversion efficiency is the degree of crush. Coarse grits don't convert as fast or completely as fine grits. Different crushes could go a long way towards explaining the wildly different efficiencies you have seen.

Brew on

I do mill my own grains. My roller mill is set at 0.032". I haven't had below 70% Extract efficiency since I used a Corona mill.

So a couple of things jump out, for starters, that's an awfully low amount of base malt, generally base malts should be at least 70% of your beer by gravity points. That's also an awfully high amount of flakes vs malts, I have to wonder if that might interfere with your efficiency; I typically don't use more than a pound of flakes in a beer and that's with a higher grain weight by at least a couple of pounds. Beyond those potential issues, how much water are you using? The thickness or thinness of your mash can have a big effect on your efficiency. Is this brew in a bag? If it's a more traditional mash, are you sparging? If so, batch sparge or fly sparge?

I'm using 10 quarts for the 6 lbs, so 1.67 qt/lb. The mash is sort of a hybrid of BIAB and conventional mashing. I've had problems with stuck mashes with my current grain crush, so instead of widening the mill gap, I use a brew bag in my cooler mash tun. After the 60 minute mash I do a batch sparge, giving it a stir and letting it sit for a few minutes before running it off.

The unmalted barley is the culprit here. Flaked and roasted grains contribute zero diastatic power to the grist and will result in poor mash efficiency when used in abundance (>30%). Typically base 2-row malt has enough diastatic power to convert itself and its weight in other starches to polysaccharides, but throw in any number of factors (mash thickness, pH, time and temperature) and you might as well cut it in half.

And while the flaked grains do come pregelatinized, the absence of a husk will produce a viscous wort that can make conversion an arduous detail and lautering a nightmare. A mash out step can really improve efficiency for extremely viscous worts. For what it’s worth, I recently brewed a black IPA with 18% flaked barley and roasted malt and experienced these issues firsthand.

So would a longer mash help with conversion or have the amylases petered out before conversion can take place? If the enzymes have denatured before all the conversion takes place, it seems that next time I would need either more base malt or less flaked barley. For what it's worth, I use Brewer's Friend to manage my recipes and it said I had a diastatic power of 70 (I assume it's in degrees Lintner). I thought I had enough base malt but their diastatic power estimates might be optimistic.

As I mention above in this post, I mash in a bag so the lautering isn't too much of a problem.

At any rate, thanks for the insights everyone. Next time I brew this, I'll have a Robobrew so I'll be able to do the all-grain version. Hopefully that'll go smoother.

 

[RM-MN]

Tighten up the mill and try again. .025 seems to work for many brewers.

 

[myndflyte]

If you're doing BIAB, then just tighten the mill as much as you can. And run it through the mill twice. Since I got my own mill and started doing that, I'm getting 90%+ conversion.