Maybe protein rests aren't a waste of time?

Today has been an interesting brew day. I'm in the midst of making a pale ale. When I started, I discovered my HLT thermometer is busted (reads 40 degrees all the time). So I heated my strike water in my boil kettle. Just as I'm mashing in, my mom calls; my dad got a flat tire on his way home with 50 bags of wood chips, and needs to unload the bags to fix the flat. I close up my cooler, jump in the car, and go help him with that.

I get back to my mash about 40 minutes later and discover the mash temperature is only about 130 degrees. I was already mashing a bit on the thin side, and I was worried about the amount of water it will take to bring the temp up, so I basically did a decoction instead; I drained the tun into a kettle, brought the wort up to 156-157 or so, and transferred it back into the tun. I let it sit like that for another 40 minutes or so.

I drained and batch sparged as normal, reasonably convinced that this batch is just going to be wonky. I don't really know how to test for proper conversion. I've tried the iodine test before, but I've never been able to read it. The wort itself looked a little different than what I'm used to seeing. Cloudier and less viscous, I guess. I grabbed a sample and tossed it in the fridge for a gravity reading. Once it had cooled down enough, I took a reading and plugged the gravity into Beersmith. Beersmith comes back with a mash efficiency of almost 87%! I usually get about 74-75% on the mash. It remains to be seen if the beer tastes right and what my total efficiency ends up being, but it seems to me like I got dramatically better conversion than I typically do.

My fear is that high quantities of unconverted starch can throw off a reading. Is that the case? If this is a genuine reading, perhaps I should start regularly doing a (smaller, shorter) protein rest in my mashes. If it were only a point or two, it wouldn't be worth the trouble, but 10+ points is a lot.

TLDR: Accidentally did a protein rest and decoction and appear to have improved my mash efficiency by over 10%.

You didnt say what your starting Mash temp was at. Did it drop that far down or did you not see what it was at?

I didn't measure it. I figured my strike water was the right temp (turns out it wasn't, not sure how I screwed that up), so I should be good. Ran out and didn't check it properly until I got back.

I'm going to try a more controlled experiment the next time I brew to see if this was just a fluke.

beertroll said:

I get back to my mash about 40 minutes later and discover the mash temperature is only about 130 degrees...

I was already mashing a bit on the thin side...

let it sit like that for another 40 minutes or so....

The wort itself looked a little different than what I'm used to seeing. Cloudier and less viscous, I guess. I grabbed a sample and tossed it in the fridge for a gravity reading...


Beersmith comes back with a mash efficiency of almost 87%! I usually get about 74-75% on the mash.

My fear is that high quantities of unconverted starch can throw off a reading. Is that the case?

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I'll take a shot at trying to analyze the brew.
(if anyone does not agree with my thoughts feel free to say so. I don't pretend to know everything)

The B.S.

First off the idea of a "protein" rest is loosing momentum. The biggest enzymatic factors at this temp is that which work on B-glucan's, there are several but for the point of this discussion we'll say B-gluconase and Solublace. Solublace has a higher working temp then B-glucanase (which is hurting at 130) so you can pull B-glucans into the mash but they wont get degraded. If you experienced a slower then expected lauter time, I would suspect you have a large degree of solubilized B-glucans in your wort. This could also be one explanation about the haze.

You also mashed for a long time starting at ~130 for 40 minutes, this would mean B-amylase would have 'chewed up' everything it could have as well as a-amylase working. Then for another 40 minutes at you mashed 156, in which a-amylase would be going crazy and B-amylase would loose its activity (probably not so fast though).

Having a thin mash also plays in here, the thinner the wort the more heat sensitive the enzymes and the 'slower' they work. However you also get more substrate (starch) dissolved in the mash, meaning potential higher gravity.

The answer

The haze could be starch haze or excess soluble B-glucans, especially if your malt was less modified/had a high B-glucan level to start with. The rest at 130 may have made the starch more accessible, which is likely the case if you had a 'sticky' grain bed or slow lautering.

Dextrins have a less of an effect on gravity then fermentables, so your high OG could be partly due to an over converted wort. Which would show up as a great Apparent attenuation, which would make the beer thinner.

My predictions on the finished beer:
It will be slightly more alcoholic and thinner then you where intending.
Probably will not be the brightest beer, to what degree depends on what is actually causing the haze (could could be a hot break problem).
It will be beer!

RDWHAHB. Check the gravity like normal worst comes to worst you made the best beer in the world and may never be able to reproduce it.

If it turns out normal you may decide to do a 15-20 minute rest from now on.

Remember that a decoction uses grain, not wort, to boil. By boiling the wort, you would have denatured any active enzymes and worked against the pH for tannin extraction.

If you ever want to do a decoction, instead of draining the wort and boiling that- boil the grain. Pull the thickest part of the mash, with just enough liquid to keep the grain from scorching. You typically don't want to pull wort and boil that due to pH issues.

beertroll said:

I've tried the iodine test before, but I've never been able to read it.

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The one problem with the iodine test that I've seen performed by many people is that they use too concentrated a solution. I dilute my iodine at about 10 parts rubbing alcohol to 1 part tincture of iodine, do the test on a piece of sidewalk chalk, and things become *much* easier to read.

Thanks for the information, all. Lots of good stuff.

Yooper, decoction was the wrong term. I didn't boil the wort; I just heated it up to the upper 150s. I guess "half-assed recirculation" would be more accurate.

Boomer, if I end up with higher dextrins than normal, that should help mask any overattenuation, correct?

The hot break was much more dramatic than I'm accustomed to seeing. Very clear wort with big flocs of stuff I assume is starch or protein. I wish I'd snapped a pic of my sight glass. After chilling, that stuff started settling out very quickly. The picture below was taken about 10 minutes after chilling, and there's already a considerable layer of trub. Post-boil gravity was only about 2 points high, and I ended up with a little less wort than planned (less runnings than expected, and I forgot to compensate for using leaf hops). I'm eager to see how the finished beer turns out.

beertroll said:

Boomer, if I end up with higher dextrins than normal, that should help mask any overattenuation, correct?

The hot break was much more dramatic than I'm accustomed to seeing. Very clear wort with big flocs of stuff I assume is starch or protein. I wish I'd snapped a pic of my sight glass. After chilling, that stuff started settling out very quickly. The picture below was taken about 10 minutes after chilling, and there's already a considerable layer of trub. Post-boil gravity was only about 2 points high, and I ended up with a little less wort than planned (less runnings than expected, and I forgot to compensate for using leaf hops). I'm eager to see how the finished beer turns out.

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It looks good, only 2 pts off isn't a huge deal in terms of how the finished beer will turn out. The large flocks may be because of the hop leafs, which tend to have a higher phenol count then pellets. Poly phenols, if memory serves me right, bind with proteins to precipitate out.

Looks like it should be a good beer, i doubt you'll notice much of a difference at this point since you basically hit gravity. May be lightly thin, but i doubt you'd notice it much. Your fermentation would have a larger effect on the flavor at this point. If you really want to see what happened try it again with out the rest.

P.S. just had a thought about your original post and your reading. Depending on how you took the sample you may have had a section of more concentrated wort (it does vary as you sparge).

It definitely finished dry. It appears to have settled out at 1.007. It doesn't seem too thin. It's definitely tasty, though it has more of an IPA character than an APA. I'm giving the yeast a few more days to clean up, and then it's getting cold crashed and dry hopped.

P.S. just had a thought about your original post and your reading. Depending on how you took the sample you may have had a section of more concentrated wort (it does vary as you sparge).

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I have run into this problem before as well. I now stir my sparged wort before I take a pre-boil reading to make sure I'm not getting a biased reading towards the first or second runnings.

I did stir before pulling my sample, but I guess I could still have had some stratification. The only other thing I can think of is that something in my wort threw off that initial reading but was removed by the hot break.