Refractometer issuessupp

[toddfore]

just bought this refractometer on sale from More Beer. Put some room temp. Distilled water on it and calibrated it. Had a beer ready for racking so I tested it and I got a reading of .025 but my hydrometer had .010 and the recipe called for a final gravity of .008. Rechecked calibration and it was correct. Made a beer and checked the preboil reading which was supposed to be .055(high gravity beer)and it read .064 but hydrometer read .054. Finished beer and was supposed to be .074 and it read same as hydrometer at .072. Why where 2 of the readings off but the 3rd one correct? It is temperature correct but the first reading I took had a temperature of 60* and it was 15 points high. Any thoughts or is this unit crap? Thanks.

Todd S

 

[myndflyte]

A refractometer is best for unfermented wort. Once there is alcohol in there, it'll change the refractive properties and give you incorrect readings. If you take your readings in Brix, you can use this calculator to convert to SG: http://seanterrill.com/2012/01/06/refractometer-calculator/

As for your pre-boil being off, did you take the refactometer sample from the hydrometer tube or just take it right out of the boil pot?

 

[jpakstis]

Yeah what myndflyte said. That Sean Terrill converter is great.

 

[doug293cz]

In addition to what previous respondents have said, if you take a sample of hot wort, you need to take precautions not to lose water to evaporation. A good method is to fill an eyedropper with your sample and let it cool for a minute or two in the dropper before placing a drop on the prism plate. If you place a hot sample directly on the prism plate and hesitate at all to drop the cover, you can lose water from the sample, which will give you a high reading. I suspect this is what happened with your pre-boil sample.

Brew on

 

[toddfore]

Ok, Idid take the sample using an eye dropper from the tube. I will wait a little net time. If I see Brix on the left and SG on the right, is the SG different tHan going to site and doing conversion?

Todd

 

[myndflyte]

Yeah I wouldn't trust the SG. Just use the Brix and then something like the Sean Terrill converter.

 

[doug293cz]

Ok, Idid take the sample using an eye dropper from the tube. I will wait a little net time. If I see Brix on the left and SG on the right, is the SG different tHan going to site and doing conversion?

Todd

Yeah, the SG readings might be different. Many refracts have a borked SG scale. You need to determine how your refract compares to hydrometer readings. Instructions for this are can be found here: https://www.brewersfriend.com/how-to-determine-your-refractometers-wort-correction-factor/ . All readings for correlation/calibration purposes should be taken on cooled wort.

Brew on