i mashed at 165 does this affect efficiency

I recently found out that my temperature gauge was out of calibration and it was out of calibration by 15 degrees and I have been mashing my beers at that temperature now. Obviously my final gravity's are very high but I was wondering if this temperature would also be affecting my original gravity and also efficiency.

The mash temp will not effect you r OG but will the FG so if you are looking at mash/lauter efficiency then no ill effect but for total brewhouse efficiency, yes as the beers will not reach the desired final gravity and of course this also assumes you met your volumes and everything else taken into consideration.

Damn I guess I'm doing somethibg else wrong my og efficiency varies from 50%-70% I assume its the LHBS grind now then.

Double-grind it next time and see if that does the trick.

duboman said:

The mash temp will not effect you r OG but will the FG so if you are looking at mash/lauter efficiency then no ill effect but for total brewhouse efficiency, yes as the beers will not reach the desired final gravity and of course this also assumes you met your volumes and everything else taken into consideration.

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I'm not sure that is entirely true. If he is mashing as high as 165F his conversion could be suffering considerably. The majority would be unfermentable which would contribute to his SG but if he is only converting a small percentage of the starch in total his OG would suffer.

Are you testing for full conversion with iodine? Really most of the starches are converted in the first 20 min or so. The rest of the time is allowing the dextrins to be broken down.

helibrewer said:

I'm not sure that is entirely true. If he is mashing as high as 165F his conversion could be suffering considerably. The majority would be unfermentable which would contribute to his SG but if he is only converting a small percentage of the starch in total his OG would suffer.

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I suppose there is the possibility, I can't scientifically back up my statement, but from a lot of reading about today's malts I'm of the impression that ya really pretty difficult to not get completed conversion.

I did not do an iodine test however when I first started mashing with what i now assume is a calibrated thermometer I was getting 70-80% efficiency and the last 4 beers I've made have been between 50-65%. I'll update this on Saturday when I brew again. Also my mash may have been as high as 175. My fg have all been at least 1.018 recently and I use a pound of corn sugar in each brew. So I would imagine it being pretty thin.

175 would denaturate/kill the enzymes so you'd have very little to no conversion at all.

This is an interesting question and one I've wondered about as well. I once posted something similar and was told mash efficiency was not altered by temp. The idea was that sugar is sugar as far as SG goes. Not sure if that is true or not. I do know that higher mash temps result in less fermentable wort, which is a good thing if you're looking for more body but not so good if you want less body in your beer.

Question for the experts. We all know grain mashed at higher temps is less fermentable compared to grain mashed at lower temperature. How and why, does this affect SG?

So my latest brew came out at 65% efficiency.

Dan said:

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Question for the experts. We all know grain mashed at higher temps is less fermentable compared to grain mashed at lower temperature. How and why, does this affect SG?

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The answer is above: the enzymes that convert starch to sugar get denatured once you're around 170F. And if the enzymes aren't working... obviously you get no sugar and thus low SG.

SpeedYellow said:

And if the enzymes aren't working... obviously you get no sugar and thus low SG.

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Not true. All dissolved solids contribute to specific gravity. If unconverted starch is present (dissolved), it will contribute to OG.

so then the enzymes are just incapable of converting the dextrins into fermentable sugars thus my incredibly high Fg. Also my efficiency could have appeared to look worse than it was because of the high temperature in my sample I now realize I was taking my samples at 85 or so degrees.

Yuri_Rage said:

Not true. All dissolved solids contribute to specific gravity. If unconverted starch is present (dissolved), it will contribute to OG.

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That doesn't disagree with what I said.

Then please explain. My statement appears to me to be exactly opposite your point.

Yuri_Rage said:

Then please explain. My statement appears to me to be exactly opposite your point.

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Well then you must be saying that mashing at 175F will give you the exact same OG as mashing at 154F, or 110F, or 210F. In other words, there's zero relationship between temp and OG. I've never tested that claim, but I can't imagine it could be so.

SpeedYellow said:

Well then you must be saying that mashing at 175F will give you the exact same OG as mashing at 154F, or 110F, or 210F. In other words, there's zero relationship between temp and OG. I've never tested that claim, but I can't imagine it could be so.

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i think he is saying that the gravity will be the same, but it won't be full of dissolved sugars, it will be full of dissolved starches.

Right -- hydrometers don't measure the fermentability of wort.

neosapien said:

i think he is saying that the gravity will be the same, but it won't be full of dissolved sugars, it will be full of dissolved starches.

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Yes, we all agree on that. Yuri_rage is also apparently saying that the starches have the same solubility as the sugars in this temp range. I didn't think that was true, but perhaps it is. I hope to never have to find out!

Can you give an example of grain bill, recent temp adjusted OG/FG, and yeast strain?

If your FG is super high, there might be more than mash temp affecting it.

Pretty much always 10# of 2 row in a 5 gallon batch. Then 2-3 pounds of specialty malts and varying between both dark and lighter beers were made

Wow - a few too many assumptions on what I actually meant! Sorry I didn't get back to the thread sooner. Indeed, I oversimplified my explanation. In fact, starches are not very soluble at all, especially below their gelatinization temperature, which is where most gravity samples are read. However, long chain dextrines are soluble, but not very fermentable. THAT is really the root of my point - long chain (unconverted) sugars and some starches will be present in higher relative quantities when mash temperature is other than ideal. While extract efficiency (brewhouse yield) will remain relatively constant across a broad range of mash temperatures, fermentability will suffer at the extremes. Unfermentable sugar content isn't necessarily a bad thing. In fact, it is the chief reason that different recipes call for different mash temperatures and times. Extremely well converted wort will ferment very completely, typically resulting in a thin bodied, dry beer, while wort that contains more unfermentable content will be sweeter with more body.

Kai did some experiments that back my claim - see about halfway down the page at this link. Note that brewhouse yield is a very flat curve, even showing a slight increase at very hot mash temps, while the limit of attenuation (fermentability) suffers dramatically as mash temperature increases. I don't know why the brewhouse yield sample size is so much smaller than the sample size for limit of attenuation, but the graph does illustrate my point.

By the way, Kai's site is an excellent and well maintained resource for understanding the science behind wort production and fermentation.

I didn't mean to kill the thread - further discussion here could be pretty valuable info.

Jonathanquist said:

Damn I guess I'm doing somethibg else wrong my og efficiency varies from 50%-70% I assume its the LHBS grind now then.

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Conversion of starch to sugar is indeed important for getting good brewhouse efficiency. Many pro breweries struggle with low brew efficiency when using grains with low enzymatic power, or when their mixing/step mashing techniques denature portions of their enzymes due to pockets of hot temperatures.

So yes, mashing too hot will prevent complete starch conversion and reduce your brewhouse efficiency.

Welcome, and i find i get ~10% bump in effec with a separate beta and alpha mash, one step at say ~150, then a second at 162....

maybe barley starch can get gel'd a bit better and squeegee out a bit more use from the alpha....