First All Grain Bad Efficiency Means High Attenuation?

Hi HBTer's

I've been lurking for quite a while and have gleaned a ton of useful and entertaining information. I finally have a legitimate question that has not (I don't think) been covered before, so I get to make my thread starting debut!!

So I did my first All Grain batch, EdWort's Haus Pale Ale about two weeks ago, everything went ok, but my efficiency sucked!! Slightly below 60% according to Beersmith, which ended up leaving me with an OG of 1.044 instead of the anticipated 1.051. Not thrilled about that, but not a big deal for my first All Grain. I mashed for 60 min at 151 and the mash temp dropped to maybe 149 by the end of the mash. I used one packet of Nottingham yeast re-hydrated. Two weeks later and the beer has finished at 1.005 a full .006 under the anticipated FG. Does Notty usually finish this low? I pitched a little high, about 76 degrees, but it was in an ice bath and dropped to 68 within 12 hours where I held it during primary fermentation. I have since ramped up to 72 in order to help clear any diacetyl (I think this works?). Does the low OG explain the low FG? Is this normal with Notty? Anything I should be doing differently?

P.S. Last weekend I did a stout and got 81% efficiency so I'm happy about that, now I just hope I can find some consistency.

P.P.S. EdWort, despite the fact that my amateurish skills didn't do it justice, I'm already enjoying the hydro samples that I've taken (a little watery due to my inefficiency I think). Great recipe, thank you and I can't wait to do it again once my process is improved.

I've done 5 all grain batches so far and have a similar situation to you. Efficiency in the high 60s with lower than anticipated FG. I think the low FG is a result of mashing on the lower end of the range which results in more fermentable wort. I am going to raise my mash temp closer to 155 to combat this and sparge higher, 175 maybe instead of 170. Hoping this will raise my efficiency.

Right- the greater attenuation will come from mashing at 151-149, not from poorer efficiency.

I made my APAs at 153 for my system, to get them to finish at 1.010 or so using a well attenuating ale yeast like nottingham or S05.

Double check the thermometer. Maybe 150 is really 147.

The first thing I would try is to get a bottle of iodophor from your HBS. When you're done with the mash, draw off a small amount of the wort and mix in a few drops of the iodophor. You should see a nice brown color. If you get a black color, you haven't converted all of your starch. This can happen if you don't mix the mash well enough and have doughballs, don't mash long enough, or have a bad pH, among other things.

With all due respect, screw the iodophor test... u get false positives too often. I got low efficiencies on my 1st AG and it was highly attenuated, resulting in a thin, light bodied pale ale. Higher mash temps will generate more dextrines, resulting in less attenuation & more body. Doesnt hurt to add some special b, carapils, vienna, or munich to increase mouthfeel. Higher mash temps will help more than recipe changes

TANSTAAFB said:

With all due respect, screw the iodophor test... u get false positives too often. I got low efficiencies on my 1st AG and it was highly attenuated, resulting in a thin, light bodied pale ale. Higher mash temps will generate more dextrines, resulting in less attenuation & more body. Doesnt hurt to add some special b, carapils, vienna, or munich to increase mouthfeel. Higher mash temps will help more than recipe changes

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I've seen other posts about this and, I am curious how do you know you are getting a false positive. Is just a matter of not hitting you're preboil gravity?

Thanks for the responses. I'll try bumping the temp up a little next time, probably get a new thermometer too just to make sure that I'm on target with the temps. I'll try to hold 153 next time.

Search iodine conversion test for a better explanation, but any grain particles will give a false reading. Many AG brewers just quit using it, some switched to the chalk method (check the wiki) to reduce false readings. Bottom line, most modern grains are highly modified and will convert in as little as 30 minutes, certainly will convert in typical 60 min mash. As far as temps go, they vary by style. Some styles should be dry and highly attenuated so lower mash temps are used. Some call for higher mash temps resulting in more dextrinous wort that won't ferment out completely. Designing Great Beers book by Ray Daniels is loaded with info on this and many other subjects. And wort composition doesn't even begin to address the differences in attenuation between different yeast strains and pitching adequate amounts of yeast.

I guess I was addressing what seemed like the real problem in the OP: the efficiency. Nottingham is pretty attenuative, so I'm not surprised he finished at that FG when mashing at 151.

I agree with everything said on this post, especially the part about Ray Daniels book. Most grains do convert right away, under the proper conditions. What if he used his extremely alkaline water on a bill full of light malts? Will you still convert if your mash pH is 6.5? Probably, but your efficiency might be 60%, causing you to miss low and end up with an over-attenuated beer. I've had false positives with iodophor as well, but the first thing to do when you have a problem is break down the process and find the fault.

The times that I've made a beer that seems kinda thin, I'll carbonate it on the very high end of the style, which helps a little.