Great attenuation on first AG

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ayrton

ayrton

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I thought my efficiency would suck, so I upped my grain bill to adjust for it. I ended up with an OG of 1.062 with 12.5 pounds of grain, and while I'm not going to bother calculating efficiency, I have a feeling that's not bad.

Anyway, I just checked my FG this morning (I transferred to secondary last night but had to borrow a hydrometer this morning) and it was 1.009, and this was with White Labs Irish Ale yeast, which is listed at 69 - 74%. Mine was over 85%! I think my mash temperatures might have accounted for it: I aimed for 153, but at the end of an hour, it was at 149. I need to find a way to keep the temperature up. I've never had a FG below 1.018, so I'm pretty psyched. :ban:
 
Well done.

Rough rule of thumb efficiency. based on approx potential of 1037 ppg from grain

OG 1062 on 12.5lb for 5 gallon (us).

62/(12.5*37/5.5=84)
_________________
100


:mug::ban:

74%

:rockin:

Well done.

And yes a lower mash temp gives a more fermentable wort. I like a little residual sweetness so up it a little.


Edit: I made a mistake I stated based on 5 gal but calculated on 5.5 gallon. at 5 gallon to the fermenter it's 67% still okay for the first outing.
 
orfy said:
Well done.

Rough rule of thumb effeciency. based on approx pottential of 1037 ppg from grain

OG 1062 on 12.5lb for 5 gallon (us).

62/(12.5*37/5.5=84)
_________________
100


:mug::ban:

74%

:rockin:

Well done.

And yes a lower mash temp gives a mor fermentable wort. I like a little residual sweetness so up it a little.
Click to expand...

Ha! Thanks. I better raise my temps a little next time, especially as this was *supposed* to be an Irish Red. It's too dark and not malty enough, so I don't know what the hell to call it. :)

Edit: do you calculate the efficiency based on the OG of the pre-boil volume and OG or the post-boil?
 
I usually measure pre-boil volume but I don't think it really matters, just do it the same each time. I too noticed a lower FG when I switched to AG but is related to rest temp and I usually am in the 151-153 range for most my brews.

EDIT - another good reason to do pre-boil would probably be if you're adding any adjuncts to the boil such as honey, brown sugar etc.
 
Post boil. (It does matter where you do it)

Here's an easier way to look at it. (The way I was doing it is messy and easy to get mixed up)

12.5lbs of grain with a potential gravity of 1037 so that at total potential

of 12.5.*1037 = 462.5

your mash gets 8 gallon at 1045 so a total of 1045*8=360 So mash efficiency = (360/462.5)*100 = 78%

So at the Kettle post boil efficiency = 5.5 gallon at 1062 = total gravity of 5.5*62=341 So (341/462.5)*100 = 74%

At the fermenter brew house efficiency: is 5 gallon at 1062 = total gravity of 5*62=310 so (300/462.5)*100 = 67%

if it was 4.5 gallon at 1060 then 4.5*62=279 so 279/462.5= 60% (beginning to suck)


You only really need to do these calculations once unless you change something or have a problem.
It's nice to know but once you dial it into the recipe and you are hitting targets then you can leave it be.
 
orfy said:
Post boil. (It does matter where you do it)

Here's an easier way to look at it. (The way I was doing it is messy and easy to get mixed up)

12.5lbs of grain with a potential gravity of 1037 so that at total potential

of 12.5.*1037 = 462.5

your mash gets 8 gallon at 1045 so a total of 1045*8=360 So mash efficiency = (360/462.5)*100 = 78%

So at the Kettle post boil efficiency = 5.5 gallon at 1062 = total gravity of 5.5*62=341 So (341/462.5)*100 = 74%

At the fermenter brew house efficiency: is 5 gallon at 1062 = total gravity of 5*62=310 so (300/462.5)*100 = 67%

if it was 4.5 gallon at 1060 then 4.5*62=279 so 279/462.5= 60% (beginning to suck)


You only really need to do these calculations once unless you change something or have a problem.
It's nice to know but once you dial it into the recipe and you are hitting targets then you can leave it be.
Click to expand...

Very complete, nice! Thanks.
 
I let ProMash do my efficiency ratings. The only reason I've done it pre-boil was because of what the ProMash help stated. But they're basically saying what I suspected regarding adjuncts. Here's a cut/paste.

-------------

Recorded Volumes:

Anytime after you have collected all the wort from the mash and after adding any additions sugars, extracts and top-up water, you can take the recorded measurement of the volume and gravity of the wort. Based on the numbers you enter, ProMash will calculate the actual gravity points obtained from the mash and then calculate your actual mash system efficiency.

You first select when/where the measurement was taken by choosing either the "Measurement Taken In Kettle" radio button of the "Measurement Taken In Fermenter" radio button.

Recording the Measurement In the Kettle:

Measurements taken in the kettle will only consider the full recorded volume in making the efficiency calculation:


While we consider the most accurate time to take the "in-kettle" measurement to be immediately before boiling, a brewer can actually record this measurement anytime from pre-boil to the end of the boil, as long as it is taken before any wort is drained from the kettle.
 

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