Strange refractometer readings

[Soma]

I brewed an IPA 4 days ago and today I pulled a sample. The readings I'm getting make no sense to me so I thought I'd ask the experts here.

OG 1.065 / 15.8P
Today: 6.75 plato.

Fermented at 68-71F for 3 days then fell to 64F which is where I took the reading. Yeast is Wyeast 1271 American Ale II.

Today it reads 6.75P. When I run these numbers through my formulas I get attenuation upwards of 90% and an 8% abv-ish beer which makes no sense to me. I know the beer isn't done fermenting yet, perhaps the amount of yeast and hop matter in solution is screwing with my readings? Any help is appreciated! I'm already relaxing as well as having a homebrew.

 

[Sherpa FE]

Possibly because alcohol throws off refractometer readings. This is the reason that I still use a hydrometer for measuring FG.

 

[bad67z]

I have not used this one personally but here is a calculator.

 

[vera]

Once your wort is fermenting, or contains alcohol, your refractometer will no longer be accurate. There is a formula that you can use, but it is somewhat inaccurate. Best just to use your hydrometer. I always use my refractometer on brew day when I'm trying to target a certain OG. Once fermenting, I use the hydrometer. The formula for using a refractometer is on the morebeer.com site.

 

[Soma]

Yeah, I am using formulas/calculators like the one linked above that adjust for refractometer use and I still get the same numbers. Guess it's time to bust out the old hydrometer.

 

[Sherpa FE]

I have not used this one personally but here is a calculator.

I have been curious lately as to the accuracy of the conversions for FG and a refractometer. What have been your findings?

If they are accurate I could definately switch to refractometer only.

 

[Polboy]

I have been curious lately as to the accuracy of the conversions for FG and a refractometer. What have been your findings?

If they are accurate I could definately switch to refractometer only.

I use both and after using online calculator for refractometer results are basically the same, i still use hydrometer at bottling as i like to drink the sample and i have beer leftovers anyway but if i break my last hydrometer im not buying new one. Refrac is very convenient, i use it multiple times during brewing and then few times to check if FG stabilized at the end of fermentation

To the OP, did you take multiple readings or 6.75 was read only once, i would check another sample as you FG of 1.003 looks really low, what FG did you expect?