Beersmith FG estimates

[christophereatworld]

Hey guys,

I'm a couple of years into brewing, but just getting to grips with Beersmith for the first time.

Just wondered how reliable it is when it comes to FG estimates. I understand it's easy for it to get a SG, IBU and ABV estimate from the grain/hop bill, but there are other factors that contribute to the FG.

For example, my recipe calls for a sub 1.010 FG, but Beersmith estimates a 1.016 FG, which would change the beer completely.

I've added my desired mash temp of 148F, which I understand is the best way to ensure a lower FG, but no change in Beersmith.

Is this something to be concerned about in your collective experience? Should I still be confident of hitting my GF or should I think about altering the recipe?

Thanks,
Chris

 

[Qhrumphf]

Need more details about the beer. A 6 point difference is certainly cause for alarm, and it could be a flawed recipe, or BeerSmith's calculations might be getting it wrong. It could go either way depending.

I've found BeerSmith's FG predictions to be pretty good until you start making things complicated. I've found it's terrible at predicting FG when adjuncts are involved (sugars, unfermentables, starchy adjunct grains, etc). It also doesn't do well with sour/Brett beers. And I've found it starts getting screwy with bigger beers too.

Basically, I let experience be my guide there. I know when to expect something a little higher than what BeerSmith spits out, and when to expect something lower.

 

[Subdivisions]

Yeast is an important factor. Do you have the correct yeast entered in?

As far as your recipe, is it a tried recipe that has gotten below 1.01 in the past?

 

[christophereatworld]

Yeast is an important factor. Do you have the correct yeast entered in?

As far as your recipe, is it a tried recipe that has gotten below 1.01 in the past?

The recipe is a Sculpin IPA clone

The yeast is: WLP001

The grain bill is:
5lbs 2-row
4lb Light DME
8oz Caravienne Malt
4oz Carapils
12oz Caramel 10L

OG estimate 1.068 / FG estimate 1.016 / ABV 6.91.

The ABV is right, but I'd like to be more in the range of 1.063 /1.008.

Thanks guys.

 

[C-Rider]

The recipe is a Sculpin IPA clone

The yeast is: WLP001

The grain bill is:
5lbs 2-row
4lb Light DME
8oz Caravienne Malt
4oz Carapils
12oz Caramel 10L

OG estimate 1.068 / FG estimate 1.016 / ABV 6.91.

The ABV is right, but I'd like to be more in the range of 1.063 /1.008.

Thanks guys.

did you hit your OG

 

[Qhrumphf]

Are you getting the batch size right? Assuming 70% efficiency out of the partial mash, 1.068 works out for 5 gallons. But 5.5 gallons puts it at about your desired 1.063. The question is whether or not the hopping lines up.

(Note: that's paper math and guesstimates of extract potential from the grains, not plugged into BeerSmith. But if the respective batch sizes are off, my point remains valid...)

 

[unionrdr]

From what I've experienced with BS2 so far, OG's are efficiency dependent with the software. My OG's are typically a few points higher since I started doing a batch (dunk) sparge. FG's are usually close or dead on. The close ones are typically a point or two lower. Any lower than 1-2 points tells me somethings off in the numbers that are plugged in for other things that Beersmith uses for it's calculations. The program takes some getting used to, what with all these numbers one has to plug in. So it's a bit of trial & error to get it to match up with what you're actually getting. And anywhere you can plug in numbers you've actually gotten, don't forget to do so. It's my opinion that the software uses these numbers in it's future calculations...

 

[christophereatworld]

Ah, man. I'm super confused now. I haven't brewed yet, it's a recipe I'm planning for this weekend, but I'm going based off a slight variation of this recipe, adapted for partial mash, with slightly different hop additions. I think Sculpin is a helluvalot dryer than 1.014, so I'm curious as to how to get it down.

Sculpin IPA 5 gal - American IPA
================================================================================
Batch Size: 5.000 gal
Efficiency: 70%
OG: 1.068
FG: 1.014
ABV: 7.1%
Bitterness: 98.6 IBUs (Tinseth)
Color: 6 SRM (Morey)

12 lbs Pale Malt (2 Row)
8 oz Cara-Pils/Dextrine Grain
1 lb Caramel/Crystal Malt - 15L Grain 16.000 oz Yes No 75% 15 L

1 oz Amarillo FWH
.5 oz Columbus @ 90 min
.5 oz Magnum @ 60 min
.25 oz Northern Brewer @ 60 min
.25 oz Columbus @ 60 min
.5 oz Crystal @ 30 min
.25 oz Centennial 1@ 30 min
.25 oz Simcoe @ 30 min
1 oz Amarillo @ 0 min
2 oz Amarillo dryhop
2 oz Simcoe dryhop

===========================================

 

[Hello]

Ah, man. I'm super confused now. I haven't brewed yet, it's a recipe I'm planning for this weekend, but I'm going based off a slight variation of this recipe, adapted for partial mash, with slightly different hop additions. I think Sculpin is a helluvalot dryer than 1.014, so I'm curious as to how to get it down.

I most certainly would not put a lot of stake into the FG estimate in BS. Based on your yeast and your grain bill, I would expect it to be at least 1.010, not 1.014. With extract, you do tend to finish slightly higher than you would if you were using all grain and no extract. I would brew it as you've posted it with WLP001. Be sure to do a starter because one vial probably won't be enough. You could pitch two vials but you're getting into $12-$13 in yeast alone, which is pricey.

 

[christophereatworld]

Are you getting the batch size right? Assuming 70% efficiency out of the partial mash, 1.068 works out for 5 gallons. But 5.5 gallons puts it at about your desired 1.063. The question is whether or not the hopping lines up.

(Note: that's paper math and guesstimates of extract potential from the grains, not plugged into BeerSmith. But if the respective batch sizes are off, my point remains valid...)

When you say batch size, do you mean the amount of water going in, or the amount I hope to end up with in the bottles? Sorry... my n00bness is showing.

 

[Qhrumphf]

When you say batch size, do you mean the amount of water going in, or the amount I hope to end up with in the bottles? Sorry... my n00bness is showing.

When i say batch size i mean the volume of wort after boil, after chilling, after top off if you top off, but before any loss to trub. If you're doing a full boil then it's your post-chill volume. If you're dumping the entire kettle (trub and all) into the fermenter and then topping up with water it's the volume you top up to. If you're separating trub out and losing some volume then that has to be factored. Some folks include it in batch size (ie this recipe could be written assuming 5.5 post boil, 0.5 loss to trub/hop matter, and thus a 5 gallon batch).

 

[christophereatworld]

When i say batch size i mean the volume of wort after boil, after chilling, after top off if you top off, but before any loss to trub. If you're doing a full boil then it's your post-chill volume. If you're dumping the entire kettle (trub and all) into the fermenter and then topping up with water it's the volume you top up to. If you're separating trub out and losing some volume then that has to be factored. Some folks include it in batch size (ie this recipe could be written assuming 5.5 post boil, 0.5 loss to trub/hop matter, and thus a 5 gallon batch).

Thanks for explaining. All of this seems quite difficult to quantify. How does one know how much is being lost, truly. The Beersmith calculations?

 

[Qhrumphf]

Thanks for explaining. All of this seems quite difficult to quantify. How does one know how much is being lost, truly. The Beersmith calculations?

I find calculating loss to be something where BeerSmith is lacking, which is why i go about it the way i do. Trub loss is very much recipe dependent and BeerSmith tries to assume it's constant when it's not. I just let experience be my guide and figure that part out on my own.

 

[jbrace1]

It must be the DME. I have the EXACT same recipe in BS but all grain with the same %s of crystal malts as in your recipe and mine is calculated as 1.068 and 1.009.

All in all i have found the OG and FG in BS to be very close to my measured values (all grain).

 

[christophereatworld]

It must be the DME. I have the EXACT same recipe in BS but all grain with the same %s of crystal malts as in your recipe and mine is calculated as 1.068 and 1.009.

All in all i have found the OG and FG in BS to be very close to my measured values (all grain).

Thanks for the feedback. Any suggestions for combating it? Someone suggested switching out a little of the DME for corn sugar.

 

[LLBeanJ]

Thanks for the feedback. Any suggestions for combating it? Someone suggested switching out a little of the DME for corn sugar.

Yes, replace some of the DME with simple sugar, e.g. corn, cane, or beet sugar.

 

[Bosh]

It MASSIVELY overestimates the FG of saisons.

 

[D-Train]

You need to add the yeast to the recipe ingredients list in BeerSmith. Then you can open the yeast properties and verify the expected low/high attenuation. I always cross reference this with the yeast published amounts. I have found that for basic single infusion mashes without adjuncts that BeerSmith is pretty good at predicting FG. Saisons being the exception. But try to do a step mash or decoction schedule and the FG prediction is way too high. In those cases, I go by experience to tell me what attenuation I should expect, and then adjust the yeast properties to get the FG prediction that I expect after using an external calculator, such as http://www.brewersfriend.com/abv-calculator/.

 

[christophereatworld]

You need to add the yeast to the recipe ingredients list in BeerSmith. Then you can open the yeast properties and verify the expected low/high attenuation. I always cross reference this with the yeast published amounts. I have found that for basic single infusion mashes without adjuncts that BeerSmith is pretty good at predicting FG. Saisons being the exception. But try to do a step mash or decoction schedule and the FG prediction is way too high. In those cases, I go by experience to tell me what attenuation I should expect, and then adjust the yeast properties to get the FG prediction that I expect after using an external calculator, such as http://www.brewersfriend.com/abv-calculator/.

Oh wow, that changes everything. Expecting an attenuation between 76 and 80 per cent (advertised is between 73-80), which I should get when mashing at 148F(?) gets me right down to 1.010.

Thanks!

 

[unionrdr]

It also bugs me how even BS 2.2 grossly over-estimates IBU's in regard to Cooper's cans. It uses the full concentrates IBU rating with out braking it down. One can is intended for 6 gallons, but it doesn't do anything with the numbers.

 

[Smellyglove]

I Would rather look at your brew-sheets for privious brews when trying to estimate FG, than looking in BS. Sure you can maybe(?) dial it in pretty nie in BS, but... I feel it's more job than it's worth, I just play a recipe by the hunch.

You can also alter the expected FG by adjusting the "base" mash temp somewhere in options.

But BS doesn't think about when you add the grains. The later you add speciality grains the higher you FG will be. Do you use pure o2 to add oxygen? what temp regime do you use for fermenting? How fresh is the yeast? Etc..