Refractometer

I purchased a refractometer with ATC this past fall. The problem I am having is that if I take a sample of the wort from my boil kettle (during the boil) my readings are way high. I will let the meter and sample sit from 5 min. or so but the reading does not change. After the boil and I chill my wort I take a new sample and the readings are then normal. Is this due to the hot break and hops in the wort or what is going on? On of the reasons I purchased this was so I could monitor my gravity reading throughout the whole process easier.

The problem is that your Refractometer doesn't work over 85F.

They perform best at 68-85F

See this link: http://cefresno.ucdavis.edu/files/43066.pdf

FYI - Most people buy them to check mash gravity and small scale brewers use them so they minimize beer loss due to testing for FG.

I appreciate the reply but if I let the refractometer and sample sit for approx 5 min. wouldn't it be within this range?

I don't know. One thinks it would. It might take longer than you think.

There was a similar thread on this same subject not too long ago. I believe this guy was brewing at pretty cool temps. He too saw that it took time to normalize.

I believe he was right on target. I think had an overnight wait. It seems temp is more critical than most people assume.

I had a similar problem. I took my wort samples from batch sparging and the wort before starting the boil, and they were always too high compared to the final boiled wort checked by my hydrometer, and compared to all my pre-brewing calculations.

This was making me crazy. I recalibrated my hydrometer in known concentrations of sugar in water, and calibrated my refractometer witt the same solutions and the two instruments were within 2% of where they should have been, and with each other, but my results were consistently off. I began to doubt my volume measurements so I calibrated by one gallon kool-aid pitcher, and it was within a couple percent too.

I finally figured out the problem. Leaving the sample (a couple ounces in an open container) to cool before the reading was letting it concentrate by evaporation of some of the water from the hot sample.

Now I put the sample in a small jar with a cap, and measure when cool, and my readings are right on the money, compared to my final hydrometer reading. I even swirl the condensation water in the upper part of the jar back into the wort.

Maybe this is what's happening to your samples as well, fast evaporation of some of the water out of the hot wort as it's put onto the refractometer lens.

Thanks, I will try this next time. I can see how that could be possible.

My refractometer came with a little eye dropper. I use this to collect my tiny wort sample. It is a 1mL dropper so the stem is very thin. I suck up my wort (at least 2 drops worth) and shake the eye dropper through the air to cool the sample in the stem. I do this for maybe 10-15 seconds, then drop the sample onto the refractometer lens. You need the let the sample sit on the lens for a few seconds (~30 seconds I think). Using this method my gravities have all been spot on throughout the entire process and the refracto has been really nice to have around. I have not had any differences when comparing with my hydrometer samples. Maybe this would work for you. Good luck!

EDIT: Or perhaps you received a faulty piece of equipment.

Boerderij Kabouter said:

My refractometer came with a little eye dropper. I use this to collect my tiny wort sample. It is a 1mL dropper so the stem is very thin. I suck up my wort (at least 2 drops worth) and shake the eye dropper through the air to cool the sample in the stem. I do this for maybe 10-15 seconds, then drop the sample onto the refractometer lens. You need the let the sample sit on the lens for a few seconds (~30 seconds I think). Using this method my gravities have all been spot on throughout the entire process and the refracto has been really nice to have around. I have not had any differences when comparing with my hydrometer samples. Maybe this would work for you. Good luck!

EDIT: Or perhaps you received a faulty piece of equipment.

Click to expand...

This is what I do as well, and I don't have any problems with my refractometer readings.

I also leave my refractometer indoors and do my readings there, because that is where I calibrated it. The documentation that came with it said it works best when the device, not the sample, is at the same temperature to which it has been calibrated. So, if you calibrated your refractometer indoors where it is 68º then take it outdoors where it is much colder, say, then that will influence the readings.

Thanks again to everyone that responded. I will try letting the sample cool in the pipette.