Question About Pre-Boil SG

[LogicBomb]

I'm new to all-grain. I've got 5 or 6 batches under my belt and use beersmith to design/calc everything for me.

I've setup my profile in beersmith to what I believe is correct (mash tun weight, volumes, losses, etc...). Just kept the default brewhouse efficiency of 72% in the profile figuring it was pretty average.

Something I've noticed is that on almost EVERY batch, despite nailing my volumes I always end up over my estimated pre-boil SG by 3-5 points. Today I did a red ale with 10 lbs marris otter and 8.8oz of roasted barley for a 6 gal batch. Estimated pre-boil SG was supposed to be 1.039. I hit 1.044.

Post-Boil ended up being just over 6 gallons (only 6 made it into the fermentor though) and it measured at 1.05, estimate was listed as 1.047.

All readings were at proper hydro temp.

Could my efficiency be higher than I think it is? Could something else be throwing off my numbers? Looking at my notes I always seem to blow past the pre-boil OG by 3-5 points. Not sure why.

 

[TechyDork]

What do you have the efficiency set to in Beersmith?

Sounds to me like you are getting better efficiency than what you are estimating.

Post up your recipe and maybe someone can help you with the efficiency calculations.

 

[dobe12]

Either volumes are off a bit or your are getting slightly better efficiency.

 

[Natdavis777]

Change your Defaulted Brewhouse Efficiency from 72% to 75% and see if helps. Should save you a pennies on grain for the next batch

 

[acidrain]

Have you measured and set your actual boil-off rate?

 

[1MadScientist]

Does your grain bill weight decrease when you increase the efficiency number? Efficiency is a variable, not fixed. It depends on the OG.

 

[DurtyChemist]

I think you're just getting better efficiency than you think. I hit 73% typically when I pay attention and have my Brewers Assistant on my iPad set to 70 or 73 I think. I've gone above that brewing but a recent batch has me second guessing my efficiency.

 

[hophop]

What's your batch size? If your volume into the fermentor is too high, you can adjust mash tun dead space and amount if trub loss in kettle accordingly.


Sent from my iPhone using Home Brew

 

[LogicBomb]

Thanks guys. On the next batch I'll design it in beersmith with 75% efficiency inputted and see if that brings me closer to the numbers I'm seeing.

I guess all things considered having high efficiency is a good problem to have.

 

[dtwhite]

No need to wait until your next batch. If you have detailed measurements from prior batches, just open up the old entries in Beersmith, update the volumes to exactly what you got, then tweak the efficiency until the SG readings are accurate. Then you'll know how much grain to use in the future.

 

[LLBrewer]

Here's what I do: I measure the preboil volume and then take a gravity reading after boil. Then I adjust the efficiency number in beersmith until until the estimated gravity matches the measured gravity. Done. No need to mess with all the other parameters.

 

[acidrain]

What do you have the efficiency set to in Beersmith?

Sounds to me like you are getting better efficiency than what you are estimating.



Post up your recipe and maybe someone can help you with the efficiency calculations.

Have you measured and set your actual boil-off rate?

What's your batch size? If your volume into the fermentor is too high, you can adjust mash tun dead space and amount if trub loss in kettle accordingly.


Sent from my iPhone using Home Brew

Thanks guys. On the next batch I'll design it in beersmith with 75% efficiency inputted and see if that brings me closer to the numbers I'm seeing.

I guess all things considered having high efficiency is a good problem to have.

That's your answer? Why did you even ask the question?

 

[LogicBomb]

That's your answer? Why did you even ask the question?

I was on the way out the door for the weekend, sorry about that - didn't want to seem like I was ignoring the replies and efficiency seemed like the most likely answer. I'm finally back now.

I stated in my first post that the efficiency was set to 72% in beersmith.

Boil off rate on my system (turkey fryer) is just about 1 gallon an hour.

Batch size is 6 gallons. I find that if I can get 6ish into the fermentor then I can fill my 5 gallon kegs completely and get a 750ml bottle or two out of it. So batch size seems to be coming out exactly where I have it set in beersmith with all my losses setup.

Recipe is as follows (Red Ale):

Type: All Grain
Batch Size: 6.00 gal
Boil Size: 7.24 gal
Boil Time: 60 min
End of Boil Vol: 6.24 gal
Final Bottling Vol: 6.00 gal
Fermentation: Ale, Single Stage
Efficiency: 72.00 %

10 lbs Marris Otter
8.8oz Roasted Barley

Mashed in 4.3 gallons of water @ 155, finished mashing temp was 150 after 60 min.
Drained MLT, Batch sparged w/ 5.2 gallons @ 175F
Pre-Boil OG: 1.044. Est was 1.039

Boiled 7.24 total gallons for 1 hour.

.5oz fuggles @ 60
.5oz northern brewer @ 60
.5 fuggles @ 15

Post-boil OG: 1.05, est: 1.047

Pitched rehydrated nottingham yeast.

Again, sorry for ignoring the few suggestions offering to help further. I do appreciate the time and effort people put into helping new guys like myself. Efficiency seemed like the easy answer and I was in a hurry so I accidentally made a jerk of myself - my bad

 

[acidrain]

No man, I was a little harsh... no reason to apologize.
Reading through your recipe and measured efficiency I have a couple of observations...
Your boil off rate is pretty low. I wish mine was that low because higher boil -off rates as measured in % is undesirable (look up melanoidins and boil off percentages). It's desirable to have a boil off rate of 20% or less. Mine is over that.
It occurred to me that you are measuring brewhouse efficiency. That is typically lower than mash efficiency because of the losses.
Just guessing, but if you have 75%+ brewhouse efficiency, you probably have 80%+ of mash efficiency.
Do you check your mash efficiency? That is really the most important measurement as it accurately tells you how your system is extracting sugars... the rest is a result of how much losses you decide to accept as part of keeping junk out of the final keg.
It sounds like you truly have very high efficiency. Now if you can consistently hit the same numbers you're golden.