16 replies to this topic

[BrewerGeorge]

I kegged a couple of beers today - a brown ale and Brit summer bitter. I'd measured their FG's with the refracto last week, and measured them again today after they were in the keg. They both went UP!I used the refracto both times (yes, I understand I need to do the math to find an FG.) Both of them went up by almost a full point Brix. I tried pure water afterward and it was indeed reading 0.0, so the refracto isn't out of calibration.I'm not sure what's going on. Could be poodles (yeast) that got stirred up during the transfer, I suppose, but I didn't think they should affect gravity. Might be time to break out the hydro tomorrow (if I can find it) just to verify the readings.I'm confused. :eh:

[3rd party JKor]

Oh, George, you're just so sweet that you must've rubbed off on the beer.

[dagomike]

I kind of lost confidence in refractometers a while ago. OK for ball park, but too flaky for consistency IMO.

[dapittboss]

My refractometer has been acting strange lately as well. I brewed yesterday and kept getting inconsistent readings preboil.

[MolBasser]

I don't think it is biologically possible for the gravity to go up.I would suggest taking a hydrometer sample...refractos are pretty sensitive to sample temperature and such. I'm playing with one at work and as of yet do not have much confidence in it.I'm getting the feeling that if you don't spend a couple of grand on a desktop temperature controlled refractometer the readings will not be consistent.BrewBasser

[Brian72]

I don't think it is biologically possible for the gravity to go up.I would suggest taking a hydrometer sample...refractos are pretty sensitive to sample temperature and such. I'm playing with one at work and as of yet do not have much confidence in it.BrewBasser

Which is why I love my hydrometer. I had a refractometer for a while and got rid of it, I really dont miss it at all. To me at the time it was just another cool toy that I spent too much money on that my $5.00 hydro could do the same...

[zymot]

I have experimented with my refroactometer. (~$50.00 from Williams Brewing). I have measured first running, second running, preboild & post chill volumes. Compared it against my hydrometer and it has always been within a very reasonable +/- against the hydrometer. Note: All but the post chill hydromter readings require a significant adjustment for temp.The most attractive thing about a refractometer is the ease in drawing and low volume required for a sample. If I worked at a big-ass brewery and pulling a pint or so of beer was not a problem, I would always use a hydrometer.Post fermentation I use my refractometer mostly as delta meter. Has the reading stopped going down? I will still do calculation and make sure my FG is in the ballpark. But when has stayed at X.x Brix for a week, it is done.zymot

[MyaCullen]

My refractometer has been acting strange lately as well. I brewed yesterday and kept getting inconsistent readings preboil.

I am wondering about this inconsistency from my own Refracto as well. I have a cheapo I got from Ebay. Any of you in the know types have any info as to proper measuring procedure?I have kept it clean, tested it with distilled water, even done a calibration test with a sucrose solution measured by weight , and it seems accurate but sometimes it isn't.I seem to get a better more consistent reading if I let the sample sit for a minute or two on the prism before checking it. I assume this is due to temperature?Does the light source have any bearing on the measurement?

[UGALawDawg]

I have no idea what the answer is. I'm just glad that the poodles meme has survived the move from the old site.

[zymot]

I am wondering about this inconsistency from my own Refracto as well. I have a cheapo I got from Ebay. Any of you in the know types have any info as to proper measuring procedure?I have kept it clean, tested it with distilled water, even done a calibration test with a sucrose solution measured by weight , and it seems accurate but sometimes it isn't.I seem to get a better more consistent reading if I let the sample sit for a minute or two on the prism before checking it. I assume this is due to temperature?Does the light source have any bearing on the measurement?

I have read the temperature adjusting portion of a ATC refractometer is for the meter, not the sample. The meter will read a given sample consistently within a certain operating range. The sample should be a certain temp for optimum accuracy.When I did my against my hydrometer tests, I wait 30-60 seconds for the sample to cool down.zymot

[HoppingFrog Brewing]

My refractor is right on for SG but jumps all over for FG I only use it on the hot side of the brewery. Works great This is why brewerys use hydrometers and often use specalyt hydrometers with finer ranges 1.020 to .980 and 1.075 to 1.040 these are easy to read

[Zulu]

I can only guess temp played part, if you kegged you also probably moved the beers into different temp zone.I use my refractometer for OG and also checking efficiency. I chose to always check the final OG with hydrometer as I also taste the wort at this stage too, no point in putting a bad beer on the yeast and waiting 5 days to know its bad.The ATC is for a set range and the advice given to me is leave it for a minute then read. For winter brewing I take it into the kitchen and leave it a few minutes to confirm - this way every time I have done a cross check with hydrometer I have been accurate.

[shaggaroo]

Could dissolved CO2 affect the reading? The only difference I can see it what you said you did is that you kegged it?? Just puttin' it out there.

[BikeBrewer]

Do you need to let the sample cool down before you put it on the plate, or can you just put it on the plate and wait for it to cool off?

[dagomike]

The thermal mass of the refracto will cool the sample. That's basically the "ATC" working. Note, however, if the instrument itself is particularly hot or cold it will throw things off.

[BrewerGeorge]

Still haven't gotten around to hydro'ing. The beers were in kegs, but they had just gone in, so they were still at 65F and very low carb. The refracto wasn't too cold or too hot. Like I said, this is weird.

[Genesee Ted]

Your beers are possessed by evil forces.... Send them to me and I will bring them to the proper authorities for proper consumption...