Who do you believe, hydrometer or refractometer?

[Litmus]

Hi All,

I have a brew currently on the go, and I'm bumping up against a trust issue.

I have two refractometers and an older hydrometer.

I have confirmed all are reading the same in distilled water. However, they are wildly different in the wort.

The two refractometer are reading 7 Brix (one has an SG scale also) so either converted or off the scale 1.027 SG.

The hydrometer is reading 1.011 SG

The wort has been in the fermentor seven days at an average of 16.5'c (Nottingham yeast).
Starting OG from the refractometer was 1.047 (bang on what the recipe said it would be).
According to the recipe, the FG should be 1.011.

The reason for my concern is I would expect the SG to be much closer to FG by now. Either way, I will leave it in the conical for another seven days.

Things I think might be affecting the reading if I go by the refractometer:

• Lower intentional temp of the fermentation

• The older malted barley I used; has been stored in an airtight container for around five months.

Push comes to shove which would you follow refractometer or hydrometer?

 

[Litmus]

Just to add, I made a starter as per the Beersmith calculator, it stood for a could of days in a cool dark place before I used it. Pitch temp on the wort was around 18'c.

 

[suffolkbeer]

Afaik refractometers (sp) don’t really work after the yeast is added?

I’m no expert so prepared to be corrected!

I always use hydrometer for SG anytime post pitch

 

[Poochops]

Hydrometer, or you have a stuck fermentation and your hydrometer is bust which unless it's in two halves, well you know...
1.047 will go to 1.011 in a week no problem as you know. No moving parts on a hydrometer and if it calibrated ok in distilled water then it's right IMO. Will be interested to see in a week what your conclusion is though.

 

[treebeard]

If you have confirmed your hydrometer reading is 1.000 in distilled water at the temperature stated on your hydrometer, then I would believe the hydrometer. There are correction factors to take into account when using a refractometer in wort that has alcohol. Hope that helps.

 

[Litmus]

All those comments help! Thanks.

Just out of interest I'm creating a control sample using sugar solution. The plan is to test, then water down by 50% and test again and so on until I reach 1.000 on both.

I also found an atenuation corrector and it seems from that things are not that far off.

 

[lancon]

7.00 brix converted to 1.027 is unfermented wort, 7.00 brix with OG 1.047 gives 1.016 on fermenting wort,, this is using Beersmith refractometer tool, and 1.011 with 7.0 brix on finished beer gives corrected OG as 1.055 (& 5.8% abv)

 

[Zephyr259]

As said above, a refractometer is only accurate in increments wort as the alcohol affects the reading once fermented. I use the brewers friend refractometer calculator to adjust for this but still I only use the reading as a way to check my gravity is stable before crash cooling. I use the hydrometer to calculate abv. I have built a spreadsheet for the conversions to check accuracy and it's normally within 2 gravity points which is often the uncertainty of my hydrometer reading. I'm using a digital refractometer though, not an optical one.

In short, looks like you hit your expected 1.011 ft dead on. Enjoy the beer. :-)

 

[Litmus]

Yeah, getting less and less concerned that something is off.

Something interesting I have discovered is the SG gradient in one of my refractometers is off, that said the Brix is reading true. Funny but good, all part of learning my way of brewing!
Brix Reads 21 and the SG scale is showing 1.080 0.0075 out when compared to the Brix to SG calculator.

 

[Litmus]

7.00 brix converted to 1.027 is unfermented wort, 7.00 brix with OG 1.047 gives 1.016 on fermenting wort,, this is using Beersmith refractometer tool, and 1.011 with 7.0 brix on finished beer gives corrected OG as 1.055 (& 5.8% abv)

So ran though this, kicked myself a few times and ended up here:

thanks

 

[GerritT]

Refractometer is nice for when checking wether the fermentation has halted, hydrometer takes a lot of brew away. But for SG? Hydrometer every time.