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Hydrometers

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Surprisingly, online discounter Zoro.com carries these at very low prices, and if you are crafty you can combine this with a promotional code to cut the price even further.  I believe they had sent me a 20% off coupon, and I got a full set of spares for less than $50 a piece.  The usual suspects sell these for upwards of $70 a piece.  You might want to check Amazon as well, you might find a lab supplier blowing out stock.

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11 hours ago, Silk City Distillers said:

Surprisingly, online discounter Zoro.com carries these at very low prices, and if you are crafty you can combine this with a promotional code to cut the price even further.  I believe they had sent me a 20% off coupon, and I got a full set of spares for less than $50 a piece.  The usual suspects sell these for upwards of $70 a piece.  You might want to check Amazon as well, you might find a lab supplier blowing out stock.

Am I correct in thinking that the cost of ttb hydros are not in the actual piece of kit but rather the lab certification?  We bought our set from cole parmer -- they were about $40 each. However, the NIST-traceable two-point calibration was an additional $145.  

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On 10/10/2016 at 7:18 PM, indyspirits said:

Am I correct in thinking that the cost of ttb hydros are not in the actual piece of kit but rather the lab certification?  We bought our set from cole parmer -- they were about $40 each. However, the NIST-traceable two-point calibration was an additional $145.  

That was my experience exactly. The glass is cheap. Certification isn't. Find a local calibration company to do it and it'll come at a better price. 

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4 hours ago, Silk City Distillers said:

Why aren't you calibrating in-house against a calibrated standard?

Are you actually able to calibrate and correct a hydrometer yourself, or are you just creating a correction table that you reference?   I am sitting here trying to imagine how I would go about changing the weight of a hydrometer in order to correct it and the only thing I can think of is sanding down the glass to make it lighter.

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If you have hydrometers with third-party calibrations - keep them locked up in the office.

Write an SOP that has you calibrating your on-the-floor production hydrometers against your standards when received, and recalibrate annually, or any time it may have been roughly handled or if physical damage is visible or suspected.  Keep records of testing and calibration.  Buy calibration stickers and put them on the hydrometer cases when you test/retest.  If you have single-point calibrations, test at the single point and record the offsets.  If you have two-point, it'll take a bit more time.

I can see using an externally calibrated hydrometer for final proofing, but for all other purposes, why wouldn't you use your house-calibrated units?  Breaking a $40 hydrometer vs breaking a $200+ hydrometer?  If you have the lab skills to gauge and proof to TTB standards, you have the skills to verify a hydrometer against a reference hydrometer.  Calibrating a hydrometer against a reference hydrometer takes absolutely no more time than gauging and proofing a batch for bottling.  I think it also demonstrates a significantly higher sense of laboratory rigor.

Your externally calibrated hydrometers should be good for a decade (or more) if only used as calibration references.  Then, it becomes relatively trivial and inexpensive to keep full sets of stems on hand.  Break one?  No sweat.  Hell, I tipped over an empty graduated cylinder the other day, and it fell onto a closed hydrometer case.  Nothing broke, didn't suspect anything, opened the case to find the stem cracked.  I swear someone else broke it and put it back in the case.

It's known that hydrometers in heavy rotation can lose mass just due to wear, wearing down from wiping, and especially when roughly handled and dropped into cylinders (and hit the bottom) - as they are known to lose mass through chipping.  Likewise, I don't particularly have much faith in that little slip of paper staying in the same place forever either.  So even if you are adamant on using third-party calibrated hydros on the production floor, are you using a third-party to validate them every year?

Or, if it's too complicated, just buy two full sets of calibrated stems every year.  But, how do you know that it wasn't damaged in shipping?  Or that the lab messed up?  Or that the tech was hungover and his dog died the night before?    Or that he wasn't rushing because he was late for a date with this really cute girl Tina from Milpitas.  Or the one-point calibration just so happened to be dead-on, but the rest of the range is significantly off?  UPS driver saw "Glass Fragile" on the box and punted it to the back of the truck.

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