Target OG consistently 10 points low

For what it’s worth, I don’t use the Brew Friend Brewday program. However, for my own procedure I do a preboil gravity that allows me to determine my Original Gravity.

For example (dramatized): If my preboil gravity is. 1.020 and my OG/Post boil gravity is to be at a 1.050, I would know I have a conversion problem in the mash or other. Whereas if I had a 1.039 preboil on a 1.050 OG/Post boil gravity, I’d be pretty confident That I’d hit the numbers.
 
I track Kettle efficiency not brew house efficiency. I can't change what I lose in trub or my mash tun and I don't dump the whole Kettle. At my volume and with my equipment I am trying to see what efficiency I am getting out of my mash and sparge process not the whole system. I have gotten my Kettle efficiency up to 83% with changes to my mash and batch sparge process. My brew house efficiency remains in the low 70s because of wort losses in my Kettle and mash tun. I'm pretty confident in the software. It nails my gravity at every step except when my efficiency gets better in which case I adjust my recipe by changing the percentage and adjusting the amount of malt I am using. If I were brewing ten gallon batches my efficiency would appear better because the losses would be nearly the same as a five gallon batch.
 
Leaving 2 gallons of wort behind will cause a big drop in overall brew house efficiency. As above if i nail my Preboil gravity I know most likely I'll nail my post boil and brew house efficiency (if I've dialed in my system to match my overall BF water profile) it should match up. Types of malt used Mash length Temperature poor boil off ect ECT will hairy the outcome.
Well I think we all can agree @lonelymtn you'll just have to brew more beer :p!
 
Trialben said:
Leaving 2 gallons of wort behind will cause a big drop in overall brew house efficiency. As above if i nail my Preboil gravity I know most likely I'll nail my post boil and brew house efficiency (if I've dialed in my system to match my overall BF water profile) it should match up. Types of malt used Mash length Temperature poor boil off ect ECT will hairy the outcome.
Well I think we all can agree @lonelymtn you'll just have to brew more beer :p!
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Like @ChicoBrewer said, I also can't help my kettle losses. As they are accounted for in my equipment profile, they shouldn't affect my brew house efficiency. I get the volume in the kettle that I expect, and outside of these last few brews, I've hit my expected brew house efficiency of 70%.

I'll definitely be brewing more. This is my 7th year (5th as all grain) and I will be brewing twice a month, if all goes according to plan. I'm hoping a few minor tweaks + ignore things that look obviously wrong, will cause this issue to go away. It is just unsettling that it has happend three times in a row.
 
So cracked open the recipe for my next brew. It believes I need to start with a 1.034 boil gravity. That will give me an OG of 1.052 after a 60 minute boil. For that to work my boil off needs to be close to 5 litres an hour. Sadly my profile has a 3 litre an hour boil off rate. So looks like I've got the same OG problem.

This is the recipe - https://www.brewersfriend.com/homebrew/recipe/view/737458/a-mirror-darkly

edit: fermenter volumes have been good and any gravity shortfalls I've been seeing haven't been consistent enough for me to care (or I've done other creative things like spilling the wort when carrying it to the stove). So could have easily missed this.
 
Just did the same mine seems spot on as per my previous batches expected preboil is a few points lower than Final gravity.
Unless I'm looking at wrong spot?
20190205_202759.jpg
 
Trialben said:
Just did the same mine seems spot on as per my previous batches expected preboil is a few points lower than Final gravity.
Unless I'm looking at wrong spot?
View attachment 5087
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No, that is the right spot. That and when you are editing the recipe. Those numbers, at least for that recipe look like what is expected. I am curious, however, do you have any recipes that are high gravity? I am wondering if the estimate is more off the higher the target OG is. At least from first glance, that is what it looks like across all of my recipes.
 
@lonelymtn - this thread has made me slightly paranoid so I'm checking this whenever I'm fidding with my recipes and I think I've found another possible explanation.

I think the recipe calculator adds the amount of water lost to dead space into the OG calculations rather than just into the volume/efficiency calculations. For me it's pretty small 0.003 and 0.002 SG points for the two recipes I'm looking at brewing soon, but for someone with a decent amount of kettle dead space it'd be a problem.

Recipe 1 -
(14.1 L @ 1.066 boil gravity) - (3.8 L boil off) - (0.2 L hop absorbtion) = 1.091 OG via the dilution calculator. But the recipe calculator has 1.094. Add the 0.2 L kettle deadspace into the dilution calculator and it gives 1.094 OG.

Recipe 2 -
(15 L @ 1.05 boil gravity) - (2.5 L boil off) - (0.3 L hop absorbtion) = 1.061 OG via the dilution calculator. But the recipe calculator has 1.063. Add the 0.2 L kettle deadspace into the dilution calculator and it gives 1.063 OG.

I've quickly checked a few more recipes and they all seem to include kettle deadspace as a loss for the OG calculation.
 
It has to add in the water lost to dead space. Dead space in the mash tun and kettle means wort is not getting into your fermentor. That means lost sugar you have to make up for somewhere and water that has to be made up as well. I dump everything into the fermentor so there's minimal loss there, adjusted in my equipment profile to zero. The mash tun is a different animal - there's always some wort trapped under the false bottom, I use about a quart in my setup.
 
Nosybear said:
It has to add in the water lost to dead space. Dead space in the mash tun and kettle means wort is not getting into your fermentor. That means lost sugar you have to make up for somewhere and water that has to be made up as well. I dump everything into the fermentor so there's minimal loss there, adjusted in my equipment profile to zero. The mash tun is a different animal - there's always some wort trapped under the false bottom, I use about a quart in my setup.
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I can see why it's in the volume and efficiency calculations. But I don't see why it would add it to the OG calculation. The OG won't be changed because you leave some wort in the kettle.
 
True. I was thinking efficiency [after a rather intense Taekwondo workout ]. That's where deadspace comes in.
 
The issue isn't that the OG will be changed because you left some wort in the kettle, the issue is that you need more grain to hit the same OG if you leave some wort in the kettle. Think of it like this.

If I need 6.5 gallons of post boil wort to get 5.5 in the fermenter (because I leave a gallon of trub in the kettle) then I need to add enough grain to hit my OG for 6.5 gallons not 5.5. If I add grain for 5.5 I will be low.

That's why I use Kettle volume not fermenter volume. I leave a gallon of trub in the kettle . . .
 
ChicoBrewer said:
That's why I use Kettle volume not fermenter volume. I leave a gallon of trub in the kettle . . .
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Ah, this sounds like a much easier hack than what I was going to try -- essentially, zero out the kettle dead space in my equipment profile and increase my batch size to account for the discrepancy.

I get why BF calculates things this way, though I am not sure it is the best way to do it. The same exact recipe(s), with the same equipment profile in Beersmith don't have the gravity discrepancy.
 
Both Ways Probably Work LOL
 
SOLVED.

Changing my target from Fermenter to Kettle fixed my problems. Adjust the ending kettle volume to get my desired fermenter volume after various losses, and all numbers are essentially spot on.

Cheers to everyone that chimed in and especially @ChicoBrewer for the suggestion!
 
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