PM efficiency and extract question

I did AHS's Lawnmower Lager yesterday. I've been tracking my volumes and gravities more closely as I approach my first AG brew so I can calculate things properly in Beersmith - next batch! So I wanted to run some numbers by you more experienced folkses to make sure I'm doing it right.

I mashed the 2.5# of base and 0.5# specialty grains at 1.5 qt/lb at 150F for 75 minutes. I sparged twice with 2.29 gallons at 168F.

Beersmith estimates 1.017 pre-boil SG with 5.1 gallons in the pot. I had 1.018, making my pre-boil efficiency 85%.

I added the liquid extracts at 15 minutes (LME and corn syrup) and ended up with 4.4 gallons at flameout, which I adjusted by 4% to 4.25 to account for cooling shrinkage. That makes 16.7% boiloff, if my calculations are correct.

After cooling I took a gravity reading - 1.049. Expected OG was 1.045. So using the dilution tool, I added about 1/3 gallon of water.

Punching the actual batch volume into Beersmith, I see the efficiency into the fermenter is only 62%. Does this mean the extract from AHS doesn't have the same potential as the extracts in Beersmith's database? I wish I had thought to weigh it beforehand to double check.

-Joe

Anybody home?

-Joe

I'm not great with calculations- but it would probably be better to check efficiency after the mash, before adding extract.

I would also suggest using no more than a total of .5 gallons of sparge water per pound of grain. You don't want to oversparge the grains. You can then check the efficiency, and add water to get to your boil volume if you're mashing a small quantity of grains.

So, mash in with 1.5 quarts per pound. Sparge with up to .5 gallons per pound of grain. Measure the volume of these runnings, and take the SG. That number and volume would be what you use to figure efficiency.

When I plug your numbers into Beersmith I get an actual efficiency of 75%. I put 4.25 gallons + .3333 gallons for a total of 4.58 gallons and a SG of 1.045. One mistake I made was I accidentally input corn sugar into the recipe instead of corn syrup, that brought the efficiency down into the 60's. But when I corrected it I got 75% from beersmith.

Thanks for the input!

Yoopernatrix said:

I'm not great with calculations- but it would probably be better to check efficiency after the mash, before adding extract.

Click to expand...

That's what I did - I took the SG of the liquid in the kettle after adding all of my runnings and top-up water. That's where I got the 1.018 for 85% pre-boil eff.

MN_Jay said:

When I plug your numbers into Beersmith I get an actual efficiency of 75%. I put 4.25 gallons + .3333 gallons for a total of 4.58 gallons and a SG of 1.045.

Click to expand...

Actual efficiency, yes, but based on the volume of liquid the efficiency into the fermenter was way low. Here's what Beersmith says, ignoring the pre-boil gravity since that includes the extracts.



-Joe

Aside from the beersmith usage questions, I agree with yooper. You way oversparged. Keep your total water per pound below 4 quarts. You had 3 pounds total so the most water you should have used was 3 gallons and that's even on the high side. Given how much you sparged, your efficiency should actually be pretty close to 99%. I THINK beersmith disregards any malt extracts or sugars from the efficiency calculation since the extraction is always 100%. I do know that beertools is like that anyway.

How fine was your crush. Did you have some flour in there?

Bobby_M said:

Aside from the beersmith usage questions, I agree with yooper. You way oversparged.

Click to expand...

Noted. That's the way Beersmith calculated things, so I was just following directions

Bobby_M said:

I THINK beersmith disregards any malt extracts or sugars from the efficiency calculation since the extraction is always 100%. I do know that beertools is like that anyway.

Click to expand...

It appears that it doesn't - I had to duplicate the recipe and delete the extract/sugar to get an accurate pre-boil SG.

Bobby_M said:

How fine was your crush. Did you have some flour in there?

Click to expand...

There was some, yes. I believe I had the rollers set at 0.040.

-Joe

I see what you are asking and you are correct, it seems beersmith is calculating something incorrectly.

Assuming beersmith's potential gravity of 36 is correct, you have a potential of about 252 points in your fermentables [(3*36) + (1*36) + (2.5*36) + (.5*36)]. Divide that by 4.58 gallons and your have 55 (1.055), that would give you 100% efficiency at 4.58 gallons. Since you have 1.045, that should have given you an overall efficiency of 81.8%, far from the 58% that beersmith is giving you.

You can see that the LME and the 2-row both have a Potential of 36 in beersmith, so theoretically you should be able exchange the LME for 2 row pound for pound but if you do this in beersmith, you get an efficiency of 81.8%, same as I calculated above. I can't believe that's a coincidence. Unless I'm messing something up here it seems like your efficiency should be 81.8%

Edit: Ok since this was bugging the hell out of me, I tried to figure out why Beersmith was calculating this way and it seems that out of 252 potential gravity points, you have 206 points extracted based on 81.8% efficiency. Beersmith then deducts 100% of the extract points (144) since it assumes the full potential of extract, that leaves you with 62 points. 62 actual points divided by 108 potential points of grains (I got 108 by deducting 144 from 252), giving you 57.4% efficiency. In essence, Beersmith is not giving you credit for the extract fermentables, it's basing it on actual fermentables you extracted from grain. So I suppose the program is calculating it correctly, it just isn't clear in how it got to those numbers.

Also keep in mind that because grain makes only a small proportion of the fermentables, even a one point mistake (1.046) in your OG can jump your efficiency from 57% to 62%.

how are you measuring your volume with such precision? 2.29 gallons of sparge water for example? I mean 0.01 gallons is only 2.5 tablespoons of water, how can you measure that accurately? Could be alot of things, but I'm going to say that it's probably more likely that your measurements were off than the extract was off. And by that I mean when you're only extracting .017 worth of sugars into 5 gallons of wort, your efficiency will change drastically with just a small amount of inprecision in either the hydrometer reading or the volume measurement.

And if the LME has a potential of 34 rather than 36, that 57% just became 65%, so you can see how easy it is to swing the numbers.

I'm measuring volume in the kettle by measuring the depth of the liquid (accurate to within 1/8") and doing a volume calculation. That's why all of my volumes are decimal instead of fractional.

-Joe

Well, regardless of efficiency, the brew is delicious! I just pulled the first pint.



A little cloudy because I forgot the Irish moss, but the flavor is fantastic.

-Joe