Quantcast

Pre-boil Volume Too High And Gravity Too Low?

Aussie Home Brewer

Help Support Aussie Home Brewer:

maldridge

Well-Known Member
Joined
21/7/12
Messages
192
Reaction score
11
Location
Melbourne
I've had another problem with my volumes and gravity. Last time I thought it was down to my beersmith inputs, and I think I made have made the same mistake somehow.
I brewed the 'fatter Yak' recipe from the DB here yesterday, and again my numbers were off.
I was aiming for a Pre-boil volume of 33.5 L but I ended up with about 34.5. Not that big of a difference you might think, but my POST boil volume was aiming for 23L into the fermenter, and I ended up with 25L with some still left in the kettle.
My gravity was off with only 1040 as opposed to 1050 that the recipe called for.
This is the second time I've had these issues. I was certain this time I had setup my equipment profile correctly in beersmith.
The first brew I made was DSGA, and he sent me a recipe sheet to match my equipment for me (2x 70L pots with 1x falsie), and that was absolutely spot on.
Can anybody recommend any particular settings I should be using? I'll upload a photo of my equipment settings shortly.
 

Adam Howard

Well-Known Member
Joined
18/2/10
Messages
511
Reaction score
63
Simple fix. Measure 33.5L as depth on a stick, when you run-off/sparge just fill the kettle to the required pre-boil volume based on your stick and then shut the mashtun valve. It's really cool when you have your volumes dialled in and at the end of the boil you hit all your numbers.

You can also recalculate your efficiency based on the 25L end of boil volume and the 1.040 gravity. You'll find that your efficiency isn't much lower than you were planning.
 

iralosavic

Well-Known Member
Joined
17/10/11
Messages
1,131
Reaction score
21
I've had another problem with my volumes and gravity. Last time I thought it was down to my beersmith inputs, and I think I made have made the same mistake somehow.
I brewed the 'fatter Yak' recipe from the DB here yesterday, and again my numbers were off.
I was aiming for a Pre-boil volume of 33.5 L but I ended up with about 34.5. Not that big of a difference you might think, but my POST boil volume was aiming for 23L into the fermenter, and I ended up with 25L with some still left in the kettle.
My gravity was off with only 1040 as opposed to 1050 that the recipe called for.
This is the second time I've had these issues. I was certain this time I had setup my equipment profile correctly in beersmith.
The first brew I made was DSGA, and he sent me a recipe sheet to match my equipment for me (2x 70L pots with 1x falsie), and that was absolutely spot on.
Can anybody recommend any particular settings I should be using? I'll upload a photo of my equipment settings shortly.
In situations like that, I'd just boil for an extra half an hour to an hour prior to adding your first hop addition - assuming you don't mind the beer being a bit darker than planned.

Getting your beersmith numbers to match the real world takes a lot of trial and error and every time you change a variable in your equipment or process, your bs calculations will be out again. I assume you've compared the recipe and equipment profile of the DSGA vs the fatter yak to find any disparities?
 

Truman42

Well-Known Member
Joined
31/7/11
Messages
3,966
Reaction score
605
Your grain absorption rate could be set wrong if your getting a higher pre-boil volume. Your grain might not be absorbing as much water as you have it set for. Also are you allowing the correct amount of wort lost in your mash tun dead space?

This could also effect post boil volume as could your evaporation rate. Do some testing and get your evap rate, kettle trub etc setup correctly in Beersmith. Everyones system is different so you need to set it based on your own testing.
 

bignath

"Grains don't grow up to be chips, son"
Joined
3/11/08
Messages
2,611
Reaction score
40
Yep, pretty much what Adam suggested.

You extracted more volume from your mash runnings, and then the flow on effect is that to hit your post boil volume you'd have to boil longer or harder (if possible).

Have a look at what your grain absorption setting is. You may have it too high, and then beersmith is telling you that you'll need more sparge water than you actually need.

By lowering the absorption figure, beersmith will recalculate your sparge water to give you hopefully the same pre boil volume, but with less sparge water to do it.

Hope that makes sense.

Also, what size are you crushing (or getting crushed for you) your grain? If your crush is too coarse, your efficiency may suffer a little, but you'll have trouble free sparging. If your crush is too fine, you'll most likely pick up a few points of gravity, but you run the risk of getting stuck sparge's if you go too fine.

Once you've got it all dialled in mate, she'll be sweet!

EDIT: Beaten, many times over....lucky i don't work in a call centre.
 

Nick JD

Blah Blah Blah
Joined
4/11/08
Messages
7,322
Reaction score
453
23/25 is 0.92

1.040/1.050 is 0.8

Your problem here is your efficiency setting in beersmith. You need to lower it by about 15%.
 

maldridge

Well-Known Member
Joined
21/7/12
Messages
192
Reaction score
11
Location
Melbourne
Thanks for the replies everybody. Whereabouts in BS do I set my grain absorbsion rate?

I've attached a pic here to show my equipment settings. If anybody has any suggestions or things to change that would be great.

In regards to comparing the recipes to the DSGA recipe, the main difference I noticed was when it came to the volumes in the mash steps. Also the boil time for DSGA was 90 min as opposed to my 60. I figure that would be different too.

DSGA mash steps:
Mash in - Add 15.00L water at 74.3 - 66 deg for 90 mins.
Mash out - Add 11.25L water at 96.6 - 78 deg for 10 mins.
Batch sparge with 2 steps (Drain mash tun, add 13.91L of 82 deg).

My fatter yak recipe (I put all the details into BS):
Mash in - Add 15.30L water at 73.3 - 66 deg for 60 mins.
Mash out - Add 7.45L water at 98.2 - 75.6 deg for 15 mins.
Batch sparge with 2 steps (Drain mash tun, add 18L of 78 deg).

As you can see a few differences in there.


Thanks guys, I'll lower my efficiency and see how I go on my next batch (won't be until the new year unfortunately).


EDIT: I just had a play with my beersmith numbers, inputting my measurements from the last brew and it's telling me my efficiency is 55%! Shithouse. How the hell do I get my efficiency up?

1.jpg
 

nala

Well-Known Member
Joined
16/2/10
Messages
262
Reaction score
46
Thanks for the replies everybody. Whereabouts in BS do I set my grain absorbsion rate?

I've attached a pic here to show my equipment settings. If anybody has any suggestions or things to change that would be great.

In regards to comparing the recipes to the DSGA recipe, the main difference I noticed was when it came to the volumes in the mash steps. Also the boil time for DSGA was 90 min as opposed to my 60. I figure that would be different too.

DSGA mash steps:
Mash in - Add 15.00L water at 74.3 - 66 deg for 90 mins.
Mash out - Add 11.25L water at 96.6 - 78 deg for 10 mins.
Batch sparge with 2 steps (Drain mash tun, add 13.91L of 82 deg).

My fatter yak recipe (I put all the details into BS):
Mash in - Add 15.30L water at 73.3 - 66 deg for 60 mins.
Mash out - Add 7.45L water at 98.2 - 75.6 deg for 15 mins.
Batch sparge with 2 steps (Drain mash tun, add 18L of 78 deg).

As you can see a few differences in there.


Thanks guys, I'll lower my efficiency and see how I go on my next batch (won't be until the new year unfortunately).


EDIT: I just had a play with my beersmith numbers, inputting my measurements from the last brew and it's telling me my efficiency is 55%! Shithouse. How the hell do I get my efficiency up?
The most obvious thing on your brewday set-up is your boil-off percentage !
You have it set to 19%, I live at sea level and my boil-off rate is 8.4%.....are you living on top of a mountain ?
If you set your boil-off rate too high..not what it actually is, the program will call for more water, which you are not actually boiling off, as a consequence, too much water in the wort, a lower OG is therefore apparent.
See attached brewday from Brewmate.

Brewday.png
 

Latest posts

Top