Equipment Calibration

[Pistol Pete]

Hey Guys - Just wondering how often you have your thermometers calibrated and at what temperature points? I didn't see anything in the gauging manuals regarding this, but from what I've read on here it seems like it's mandatory.

Also, what about your floor scales and hydrometers? Are the rules for them the same as well?

Thanks!

[will]

according to the manufacturers, once you have a calibration chart, usually 5 points between 32 and 124F, checking with a distilled water ice bath is a sufficient calibration check to determine if the instrument has been damaged. Keeping records of these checks is a good idea.

Scales are a bit different. You can take some object that's about 1/3 of capacity, and that won't change weight over time, like an old anvil, and use that as a check from time to time. Check it initially when you get the scale or when it's calibrated, then use the weight as a sanity check.

Hydrometers are relatively difficult to check on your own, unless you have a bigger better instrument to check it against. We keep our calibrated hydrometers in a locked cabinet, and use them occasionally to check other hydrometers we use for production. We have a cylinder that will float two hydrometers.

Good luck,

Will

[Rumrunner74]

Is there a standard sized cylinder for hydrometers? I usually use the same cylinder for checking proof but I had something else in it and decided to use a different sized cylinder. Went from a 750ml to a 1000ml. The proof went higher in the larger cylinder. I thought it was odd so when I emptied the cylinder I usually use, I drew off back to back samples and checked them side by side. They read about 1.5 proof off from each other. Thoughts?

Jeff

[will]

is one of them plastic?

[Pistol Pete]

Thanks Will - Do the calibration points matter? One thermometer I was looking at has 5 points: 32, 40, 60, 100, 120°F but that is a mercury thermometer which is illegal in my state. Another thermometer is has 6 points: 32, 50, 68, 86, 104, 122°F Will the fact it's not calibrated at 60 matter? Thanks again

Hi Jeff- that doesn't sound right to me, my knowledge is limited so take this with a grain of salt, but I don't think the size of the cylinder should influence the reading of the hydrometer.

[Rumrunner74]

is one of them plastic?

Yes, one is plastic the other is glass. We usually use the plastic ones for checking proof.

[Max Action]

Is there a rational explanation why a glass cyclinder would differ from a plastic one? Maybe static charge on the plastic or something?