Hydrometer vs Refractometer

[C-Rider]

I bottled a Blonde today. Hydrometer said FG was 14, Refractometer read 7 brix which I converted to 28. Something is wrong. I know alcohol affects the brix reading. So what do I use for FG?

 

[marubozo]

Use the hydrometer, especially if you know it's relatively accurate. If you aren't sure, calibrate it by putting it in some distilled water.

But while there are calculations out there to adjust for alcohol content so you can use a refractometer, I never even bother using it with fermented wort.

 

[waldoar15]

I use a refractometer on the hot side and a hydro on the cold side. Just seems easier to have both. <shrug>

 

[Yooper]

I use a refractometer on the hot side and a hydro on the cold side. Just seems easier to have both. <shrug>

Yes, me too. Refractometer for preboil gravity and post boil gravity. Hydrometer for finished beer. I used a calibration tool on Beersmith for both, and I find that the preboil reading is the same for refractometer and the hydrometer but for post fermentation for my beer and wine, it's always the hydrometer!

 

[C-Rider]

Yes, me too. Refractometer for preboil gravity and post boil gravity. Hydrometer for finished beer. I used a calibration tool on Beersmith for both, and I find that the preboil reading is the same for refractometer and the hydrometer but for post fermentation for my beer and wine, it's always the hydrometer!

The refractometer is calibrated or give readings at 20*C. Do you let the hot wort cool and then take a reading or do you have a table with corrections for temp differences?

 

[Yooper]

The refractometer is calibrated or give readings at 20*C. Do you let the hot wort cool and then take a reading or do you have a table with corrections for temp differences?

My refractometer has ATC for under 100 degrees or so, I believe. A drop of wort on a cool refractometer will cool very quickly anyway, though. I just drop mash temp wort right onto the refractometer.

If the wort is actually boiling, I let the pipette cool just a tad after drawing off the drops but it's probably not necessary.

 

[fxdrider]

I'm having this same issue. I have a Honey Brown Ale in the fermenter for 9 days, and I thought I'd test out my new Refractometer to get my SG. My refractometer has both a Brix scale and a Specific Gravity scale. On Monday, when the wort was just 6 days old, I got a hydrometer reading of 1.020. Today, much to my surprise - my new refractometer got a reading of 7.0 brix/1.028 SG. WT_!!!!!!!! So, I sanitised my beer thief and hydrometer and took a reading with it, and it read 1.014. Now THAT'S more like it. This is 68° wort. I can't for the life of me figure out why there would be such a difference. My Hydrometer reads 1.000 in distilled water, as does my refractometer. I going to trust the hydrometer on this one, and just use the refractometer on the hot wort. Though, I'm not so sure I should trust it there either.

 

[ajf]

You cannot simply multiply the brix by 4 to get the gravity of a beer. If there is any alcohol in the sample, you need to use some sort of algorithm to account for the alcohol.
Most brewing software programs have a calculator, but I have never found them to be accurate. That is why waldoar and Yooper say to use a hydrometer once fermentation has started. That's what I do as well.

-a.