efficiency

[Mustard]

Hey guys I'm on my about 5th AG brew. And having problems with hitting OG. Stuck around 57-60% efficiency. Originally thought it was because of mash temp. aiming for 152 and was hitting 148. I'm in boiling a IIPA right now and hit 155 mash...batch sparged for 10 min at 170. took reading and got 1.050 (should of been 1.066). PH was in good range. Fermentables were 15.5 lbs 2 row...1lbs 60L 1 pound black patent. Milling grain at .028....

Any ideas on what might be going wrong?

Thanks

 

[TechyDork]

My first thought was your crush, but if your mill gap is at .028 I would think your crush should be good.

What is your mash process like? (Mainly how much water are mashing with and then sparging with? Are you stirring the grains prior to your sparge?)

What do you use for a mash tun?

What do you use for a filter in your MLT? (Bazooka Screen, false bottom, manifold .....)

Are you hitting your predicted pre-boil and post-boil volumes?

 

[EJay]

I'm in boiling a IIPA right now ...took reading and got 1.050 (should of been 1.066).

Wait a sec - if 1.066 is your recipe OG, that is after the boil, so you may be in fine shape. Gravity goes UP during the boil due to water (but not sugar) boiling off.

 

[Mustard]

Mashing at 1.5 q/lbs so 7 gallons stirring at begging mid way and end mash.. sparge with 3.75 g and hit 8 gallon yield. ...bit higher then I was aiming for 5.5 gallon batch

 

[Mustard]

Rectangle 48 qt cooler for tun...I use a manifold which I did knock off while stirring so I grabbed my neighbours mesh filter with siphon

 

[McKnuckle]

8 gallons into the fermenter when it should have been 5.5? No wonder your OG is low. That's very diluted vs. what the recipe specifies. You need to hit liquid volumes to match recipe stats.

 

[Mustard]

No 8 gallons into the boil....

 

[phug]

what was your anticipated preboil volume? 8 gallons at 50 points per gallon is 400 points, boil that down to 5.5 gallons, you still have 400 points, but it's now 80 points per gallon. if you boiled all 8 gallons of 1.050 wort down to 5.5 gallons, you'd be left with 1.072 wort.

you lost 3.75 gallons to grain absorption and other losses. I think that's where some of the efficiency is going. but then again the my grain loss is about 150ml/lb so .7 gallons would be what I would expect to lose from a 17.5lb grain bill. but that's BIAB

 

[mongoose33]

I think the people above have nailed it as far as when and how you're calculating gravity.

As far as efficiency, my first AG had a weaker efficiency than I would have liked.

One of the things I changed after that was making sure I stirred my mash a couple times during the hour of mashing, and stirring the batch sparge as well. Helped a great deal.

 

[doug293cz]

How did you determine your 57-60% efficiency? Given your grain bill and volumes, I get your maximum possible pre-boil SG as 1.0528 (100% conversion efficiency, 76.85% lauter and mash efficiency.) Since you got 1.050, that puts your conversion efficiency at 94.2%, lauter efficiency at 77.18% and mash efficiency at 72.68% (the numbers aren't really as accurate as given, just too lazy to do the rounding.)

You don't really have a low efficiency problem for the brew and process you used. You might have been able to get a little higher conversion efficiency (with a longer mash), but not a lot higher. Your volumes show an excess of about 3/4 of a gallon retained in your MLT, either due to higher than normal grain absorption (usually about 0.125 gal/lb), or excessive undrainable volume. Without the excess retained volume, your mash efficiency would have been about 4.5% higher, and your pre-boil SG would have been about 1.053 (assuming you used 0.75 gal less water to start with.)

Results are from my custom batch sparge simulator.

Brew on