Hi,
Why is my FG appearing as if it's going to finish so high at 1.039? (Day 2 of 1.039.) The OG was 1.073 (calibrated refractometer @ 20⁰C). The beer was delicious last time I brewed it. Anything I should consider on changing? Ingredients
0.43 kg White Wheat Malt
Mash (10.3%) -4.7 EBC
0.43 kg - Pale Malt (2 Row) US Mash (10.3%) -3.9 EBC
14.0 g-Hallertauer Mittelfrueh
Boll 60 min (7.3 IBUS)
14.0 g Hallertauer Mittelfrueh
Boil 60 min (5.7 IBUs)
2.35 kg - Wheat Dry Extract
Late extract addition: 20 min (57.2%) -15.8 EBC
170.00 g - Orange zest
Boil 5.0 min
170.00 g - Coriander Seed
Boil 5.0 min
0.91 kg - Cane (granulated) Sugar
(Post gravity reading; pre-yeast pitching)
1 pkg - SafBrew Ale
DCL/Fermentis #S-33
Topped off to 18.93 liters / 5 gallons of water.
If your OG is 1.037, your FG can't be higher. Also, get a hydrometer. Refractometers aren't accurate when alcohol is present.
I'm assuming you transposed those measurements... If so, give it a good swirl and RDWHAHB
You are right, I did invert those numbers. I have since corrected it to 1.073. I thought a refractometer wouldn't be accurate when carbonation was present. So I made sure the beer was flat before testing it.
The refractometer should be able to deal with carbonated beer pretty well, actually. And it's true that refractive index alone won't give you a sugar concentration measurement if there's also alcohol present. However, a specific gravity reading with a hydrometer also doesn't give you a sugar concentration measurement if there's alcohol present.
Interesting!! That got me to wondering, so I just took another gravity reading and here were the different variables:
First reading an hour ago:
Flat beer @ 21⁰c/70⁰f: 1.039
New reading just now:
Carbonated (2.5vol CO2) @ 27⁰c/80⁰f: 1.039
Fascinating!
(BTW, I'm pressure fermenting this in a keg.)
Refractometers are perfectly accurate enough for our purposes, even with alcohol present, if one inputs the original (incl. the sugar) and current gravities in Brix into a refractometer calculator.
Post time 2022-10-3 16:41:24
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