First Partial Mash Efficiency

[passing4sane]

A few days ago I did my first partial mash. The grain bill was:
3 lb. Maris Otter
1 lb. Flaked Oats
.5 lb. Pale Chocolate
.5 lb. Roasted Barley
.25 lb. Flaked Barley
.25 lb. Crystal 60L
.25 lb. Crystal 40L

I used 1.5 quarts of water per pound of grain and hit my temp of 155. After half an hour it was dropping below 150 so I added a quart of boiling water to bring it up. A half hour later I drained it and sparged with water around 170. I collected 3.25 gallons which is as much as my pot can hold. I got a SG of 1.057. Added a 3.3 lb. can of liquid extract, boiled, cooled, added to fermenter and topped up to 5 gallons. I got a SG of 1.041, quite a bit lower than the estimate of 1.054. I knew one of the readings had to be wrong so the next day I took another one since there weren't any signs of fermentation yet, and got the same thing. I added 1.5 lb. of dry extract to get it to where I want, but this means that the SG of the 3.25 gallons that I collected was probably around 1.027 which would put my efficiency at something like 45%. How can I get better efficiency?

 

[chiefbrewer]

I got about 48% efficiency on my first partial. I think it had to due with not hitting my target temp perfect. Also, I noticed that after I took my spent grains out and set them on a plate...a WHOLE LOT of wort eventually seeped out onto the plate, and all over the counter. Next time I am going to use a suggestion I read on these here forums that involves using a large pan (like one of those disposable roster pans at the store). After I THINK I have drained all of the wort out of the grains, let the grain sack sit in the pan and a bunch more will come out...then dump it in and boil.

 

[BendBrewer]

You lost me. You took a reading of the wort before adding extract and it was 1.057?

Then you 'assume' later in your post that it was really 1.027? Why don't you trust the reading that you took?

 

[chiefbrewer]

I believe the OP's 1.057 was a partial boil reading.

 

[BendBrewer]

I collected 3.25 gallons which is as much as my pot can hold. I got a SG of 1.057.

I added 1.5 lb. of dry extract to get it to where I want, but this means that the SG of the 3.25 gallons that I collected was probably around 1.027

I'm still lost.

 

[Bobby_M]

Sounds like the 1.057 was after the 3.3lbs of lme went in.

Describe your sparge process...

 

[Calder]

I don't understand the 1.057. I think that is probably a wrong reading as the OP said. 57 x 3.25 = 185 points. He used 5.75 lbs of grain so it equals 32 points per pound. That's about 90% efficient.

The 1.041 is his gravity of 5 gallons with the LME mixed in. The LME would give him 1.024 in 5 gallons, so he is assuming the grains gave him 1.017 (the remaining gravity points). 17 x 5 (his final volume) / 3.25 (his PM volume) = 26, or 1.026 (this is his 1.027). This is about 15 points per lb of grain.

15 points per gallon is too low.

I think either he did not adjust for temperature or the PM/LME did not mix well with the top-up water.

To the OPs question. I think you are doing fine. I would maybe cut down on the water to 1.3 qts/lb, to give yourself more sparge water, and maybe limit the PM to 5 lbs of grain, again to give yourself more sparge water.

I do 5 lb PMs (occasionally more), mash with 1.3 qts/lb. Sparge with 1 qt of water/lb twice (that is I sparge twice), and end up with about 3.5 to 3.75 gallons and my efficiency is usually 80% (sometimes higher). I find I can boil this comfortably in a 5 gallon pot.

 

[ajf]

My understanding of the OP is that he ended up with a gravity of 1.057 prior to boiling, and prior to adding the 3.3 lbs LME.
If this assumption is correct, then the sparge runnings would = 3.25 * 57 = 185 points.
Add to that 185 points 3.3 * 37 = 122 points, and you get 307 points.
Divide that by 5 gallons (the volume after topping off) and the gravity would be 1.061 (assuming zero losses during racking).
I think he got a higher efficiency than he thought, and that the probable cause of his 1.041 reading was insufficient mixing of the top off water with the wort.

-a.

 

[passing4sane]

For anyone who is confused Calder was correct with what he was saying. The 1.057 is without the lme, just the 3.25 gal I pulled from the mash. I know the 1.041 is right because I checked it again after I made sure it was mixed well. My sparge process is just a simple batch sparge. I think I will use less grains in the future and a little less water in the mash to allow myself more sparge water.