Way off estimated FG

[s_catz]

Hey all

My last two brews (summer citrus wheat, and Rye IPA) have been 10 to 15 points off the estimated FG. Is there any reason this is happening? Anything I can do to fix this issue? The have both been in the primary for 2 plus weeks and the readings have been steady for a 5 days

Thanks

 

[usfmikeb]

There are a few potential reasons for this:

- Were you at the correct original gravity?
- What was the attenuation rate on the yeast?
- What temp are you fermenting at?
- If this is all grain, what was your mash temp?
- Are you using a refractometer that isn't calibrated?

 

[s_catz]

There are a few potential reasons for this:

- Were you at the correct original gravity?
- What was the attenuation rate on the yeast?
- What temp are you fermenting at?
- If this is all grain, what was your mash temp?
- Are you using a refractometer that isn't calibrated?

Hi usfmike

my OG was correct
I have no idea about the attenuation rate
I am fermenting at 70
I believe the mash temp for both was 154
I am using a hydrometer

 

[Yooper]

How did you determine your target FG?

 

[usfmikeb]

Is there anything in the recipes that is unfermentable?

 

[s_catz]

How did you determine your target FG?

Hi Yopper

It was determined with beersmith, and also from the recipes that I am using.

 

[s_catz]

Is there anything in the recipes that is unfermentable?

No it's all fermentable

 

[Yooper]

Hi Yopper

It was determined with beersmith, and also from the recipes that I am using.

Well, Beersmith isn't really good for determining FG, as it just gives you a "standard" % for FG, and doesnt' take into account any unfermentables or fully fermentables like corn sugar. My experience is that you have to guestimate the FG yourself.

If you give us a typical recipe with mash temps, we could help you figure a probably FG and then figure out why it's not getting there.

 

[usfmikeb]

Are you using the yeast that's included in the recipe? Is it fresh yeast, or are you banking?

 

[pohldogg]

When was the last time you calibrated your thermometer? 154 is high enough that if your thermometer is reading even a few degrees low you'll really start to lose fermentability. Also, what did you do for oxygenation? I've had batches stall from poor aeration. What were the OGs?

 

[usfmikeb]

How are you aerating the wort?

 

[usfmikeb]

Great minds think alike!

 

[s_catz]

Well, Beersmith isn't really good for determining FG, as it just gives you a "standard" % for FG, and doesnt' take into account any unfermentables or fully fermentables like corn sugar. My experience is that you have to guestimate the FG yourself.

If you give us a typical recipe with mash temps, we could help you figure a probably FG and then figure out why it's not getting there.

this is the wheat mashed at 154
6.00 lb White Wheat Malt (2.4 SRM) Grain 54.55 %
4.00 lb Pale Malt (2 Row) US (2.0 SRM) Grain 36.36 %
0.50 oz Cascade [5.50 %] (60 min) Hops 8.9 IBU
0.50 oz Cascade [5.50 %] (15 min) Hops 4.4 IBU
1.00 oz Cascade [5.50 %] (5 min) Hops 3.5 IBU
0.25 oz Orange Peel, Bitter (Boil 5.0 min) Misc
0.25 oz Orange Peel, Sweet (Boil 5.0 min) Misc
1 Pkgs American Wheat Ale (Wyeast Labs #1010) Yeast-Ale

 

[Yooper]

this is the wheat mashed at 154
6.00 lb White Wheat Malt (2.4 SRM) Grain 54.55 %
4.00 lb Pale Malt (2 Row) US (2.0 SRM) Grain 36.36 %
0.50 oz Cascade [5.50 %] (60 min) Hops 8.9 IBU
0.50 oz Cascade [5.50 %] (15 min) Hops 4.4 IBU
1.00 oz Cascade [5.50 %] (5 min) Hops 3.5 IBU
0.25 oz Orange Peel, Bitter (Boil 5.0 min) Misc
0.25 oz Orange Peel, Sweet (Boil 5.0 min) Misc
1 Pkgs American Wheat Ale (Wyeast Labs #1010) Yeast-Ale

Well, how big was the starter? And the OG and the projected FG?

 

[s_catz]

Are you using the yeast that's included in the recipe? Is it fresh yeast, or are you banking?

One was safale 05 and the other was cultured wyeast 1010 that I pitched with a starter.

I just stir the wort for a while before I pitch to oxygenate

 

[s_catz]

Well, how big was the starter? And the OG and the projected FG?

I believe I did a 1litre starter FG 1.046 OG 1.011. I'm getting 1.020

 

[Yooper]

I believe I did a 1litre starter FG 1.046 OG 1.011. I'm getting 1.020

That should finish at about 1.014-1.016 or so with a mash temp of 154ish.

Can you double check the calibration of your thermometer? I would expect 1.020 or so if you mashed at 157-158.

 

[s_catz]

That should finish at about 1.014-1.016 or so with a mash temp of 154ish.

Can you double check the calibration of your thermometer? I would expect 1.020 or so if you mashed at 157-158.

yes I will check the thermometer. Im not sure if it makes a difference but I used the biab method for these batches

 

[cms]

Were they too high or too low? Or one of each?

I tend to overshoot (lower than expected) my estimated FG's (according to BeerSmith) by 4-5 points. I have come to believe that my hydrometer is not quite right (I measure plain, boiled and cooled water at 0.992).

For starters, try to calibrate your instruments. After that, is there any other evidence that your FG is off - e.g. does your post-conditioned beer taste overly sweet or dry?