What the heck happened to my efficiency?? Double IPA

[smokyjoewood12]

Ok I have not been able to figure out the solution to my problem. My efficiency is typically around 75-80%. I brewed a double ipa yesterday shooting for a OG of 1.096. Preboil gravity according to brewers friend was to be 1.054, ground my grain as usual, mashed at 153, nailed a 5.4 mash pH, hit a 1.052 preboil gravity (basically dead on). Boiled and then added my 2 lbs of dextrose at knockout. Was aiming for 6gal, only ended up with about 5 and a OG of 1.080 counting for the under volume and under gravity I hit only about 50% efficiency! whaaaat is going on?? I can't figure out how my preboil gravity could have been dead on but my postboil was so much lower than expected!! please help!

 

[sandyeggoxj]

How are you measuring gravity on the hot side of the brew house?

 

[Arrheinous]

How many pounds of grain do your 75-80% eff recipes take up? Doubling your typical amount of grain will lower efficiency because you can't extract all the sugars without using more water. I posted my experiences with this a while ago; going from 10# to 20# brought my efficiency from ~80% to 65%.

 

[zachattack]

Is this your first high gravity brew? It's very common for efficiency to drop a good bit as the grainbill gets heftier. As posted above you have less sparge water per pound of grain. Next time you can keep some DME on hand to correct the gravity and assume a lower efficiency on big beers like this.

 

[smokyjoewood12]

How are you measuring gravity on the hot side of the brew house?

cooling wort, and then refractometer.

And no not first high gravity, haven't had a problem with efficiency before. The main thing I don't understand is that my preboil gravity was right where it should have been. Which means that I extracted exactly how much sugar the software was expecting right? Because of that I feel like theres something funky goin on with the dextrose. I couldn't matter when you add it to the boil could it?

 

[stratslinger]

Could be a sampling error on either end too - if you didn't mix the wort adequately prior to taking either of those samples, you could have gotten wort that was more or less concentrated than what was average for the entire volume. What was your pre-boil volume? I'd like to run the numbers and see if your post boil measurement adds up...

 

[Black Island Brewer]

Could be a sampling error on either end too - if you didn't mix the wort adequately prior to taking either of those samples, you could have gotten wort that was more or less concentrated than what was average for the entire volume. What was your pre-boil volume? I'd like to run the numbers and see if your post boil measurement adds up...

+1
I've had to take multiple refractometer readings after stirring my wort thoroughly to get consistent results. I've started taking both a hydro sample AND then taken the refrac sample from the flask before it cools, cooled the refrac sample and measured. I can get wildly erratic readings taking my refrac sample right from the kettle.

Rereading your post, though, you didn't mention your preboil volume. Was it also dead on? If your preboil volume was low, then you didn't have as much sugar even if your gravity was correct.

 

[smokyjoewood12]

+1
I've had to take multiple refractometer readings after stirring my wort thoroughly to get consistent results. I've started taking both a hydro sample AND then taken the refrac sample from the flask before it cools, cooled the refrac sample and measured. I can get wildly erratic readings taking my refrac sample right from the kettle.

Rereading your post, though, you didn't mention your preboil volume. Was it also dead on? If your preboil volume was low, then you didn't have as much sugar even if your gravity was correct.

AHHH thats what it was!! I did multiple samplings, so I know they were on point. It was the preboil volume! I forgot that I had assumed 10gal preboil but didnt use enough sparge and only had about 7.5 so I DIDN'T hit my extraction. Got a new mill so I'm thinking the grind is the culprit. Thanks guys I knew it must have been an oversight somewhere.

 

[stratslinger]

See, that still doesn't add up though, if your starting volume is truly 7.5 and final volume was truly 5. Here's my math:

7.5 gallons at 1.052 = 7.5 * 52 = 390 GU

5 gallons at 1.080 - 0.015 for the dextrose (see math below) = 5 * 65 = 325 GU

Now, if you had finished off at the 6 gallons in you kettle, you'd still have 390 GU left and it'd work out perfect. But by this math, you lost gravity points during your boil. That doesn't happen. There has to be a sampling error somewhere, or a measuring error in your volumes.

* I arrived at the .015 for the dextrose because dextrose has 37ppg (points/pound/gallon), so 37*2/5=14.8, call it 15

 

[smokyjoewood12]

See, that still doesn't add up though, if your starting volume is truly 7.5 and final volume was truly 5. Here's my math:

7.5 gallons at 1.052 = 7.5 * 52 = 390 GU

5 gallons at 1.080 - 0.015 for the dextrose (see math below) = 5 * 65 = 325 GU

Now, if you had finished off at the 6 gallons in you kettle, you'd still have 390 GU left and it'd work out perfect. But by this math, you lost gravity points during your boil. That doesn't happen. There has to be a sampling error somewhere, or a measuring error in your volumes.

* I arrived at the .015 for the dextrose because dextrose has 37ppg (points/pound/gallon), so 37*2/5=14.8, call it 15

Correct me if I'm wrong but If I lost about a gallon due to hops (I used more than a pound of whole cone) that would account for the 6-5 gallon difference, the hops wouldn't selectively soak up pure water and leave the dissolved sugars behind. So the loss due to hops would not increase the molarity of the sugar in solution it would just take out a gallon of wort and not change the gravity. (that is my 5 gallons was ferm volume not post boil volume)

 

[duboman]

There is no way you lost a gallon of wort to a pound or pound + of hops. Somewhere your measurements or readings are off during the process.

 

[youreanimpulse]

There is no way you lost a gallon of wort to a pound or pound + of hops. Somewhere your measurements or readings are off during the process.

No offense, but I disagree. I regularly lose a gallon to hop matter in big ipas. To the point that I now strain through a fine mesh bag and squeeze the crap out of it to get it back. Granted, I use pellets. But my brewing partner uses whole leaf on his system and has the same experience. That's why all the Pliny clone kits calculate 6 gal post-boil for 5 gal in the fermenter.

 

[stratslinger]

Correct me if I'm wrong but If I lost about a gallon due to hops (I used more than a pound of whole cone) that would account for the 6-5 gallon difference, the hops wouldn't selectively soak up pure water and leave the dissolved sugars behind. So the loss due to hops would not increase the molarity of the sugar in solution it would just take out a gallon of wort and not change the gravity. (that is my 5 gallons was ferm volume not post boil volume)

OK - this _might_ make sense, but I still need you to help me with the figures a bit.

When you originally said you wound up with 5 gallons at the end - did you mean in the fermenter? If I'm reading the above correctly, it sounds like you had 6 gallons left in the kettle, drained off 5 into your fermenter, and left behind about a gallon with your hops and trub. This would then make sense, and your numbers would all seem to add up correctly.

Assuming this is correct - if you only missed your pre-boil gravity by 2 points, yet you did not hit the post boil gravity projected by BeerSmith, then maybe you need to take a look at the boil-off rates you have plugged into BeerSmith? Basically, the sugars are all there - it sounds like BeerSmith was expecting you to boil off more than you did, so your wort would be more concentrated and have a higher gravity.