Using VST outside temperature range

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CwD
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#1: Post by CwD »

So, it's winter here, and because electric heat is stupid, I just put on a sweater and keep my place at about 50-55f (about 10c-13c)

My VST does not like this. Outright refuses to measure anything outside it's temperature range, the low end of which is about 59f (15c). I'd rather not waste a lot of unnecessary energy just to use my VST, so does anyone know a way around this? Am I just going to have to get a small space heater to blast directly on the VST?

jpender
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#2: Post by jpender »

According to the documentation the VST has temperature compensation but the lower limit is 15°C. And for best results distilled water calibration should be performed within 2°C of the temperature that samples are tested at, which should also be the same temperature as the VST itself. At least if accuracy is a concern.

I've got my sample containers, recipes, and procedure laid out. I was going to brew, filter, fill the containers, and ship them to you tomorrow or Tuesday at the latest. Should I hold off on that until summer?

The guy I sent samples to before tested all the samples I sent him at 20.0±0.5°C.

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TomC
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#3: Post by TomC »

What's the deviation outside of 15°?
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CwD (original poster)
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#4: Post by CwD (original poster) »

There is no deviation outside 15c. It just outright refuses to measure the sample at all.

I've no problem bringing the temperature up for a few hours for testing a batch of samples when accuracy is most important for an experiment like that. I just don't want to do it every single day for multiple measurements hours apart. I don't especially want to need to adjust the thermostat in advance of every single brew and can't reasonably keep it 15+c in here all day.

So preference #1 would be just turn off the limit and accept it's not quite as accurate as it would be a little warmer. And preference #2 being heating the area immediately around it without wasting energy heating the whole place.

Edit: Eh, I'll just keep it warmer for now. Not that big a deal anyway.

RyanJE
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#5: Post by RyanJE »

Do you have a large enough pocket to put it in? Store it and a small dropper bottle of water in your pockets for a bit! :)
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yakster
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#6: Post by yakster »

Maybe you could place a heat lamp over a work area for your measurements.
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jpender
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#7: Post by jpender »

We keep our house at ambient temperature too so if I had a VST I'd have the same problem.

You want to have the refractometer and the samples all at a nice stable temperature. So a heat lamp sounds like a dicey solution unless you just want some number and don't mind if the accuracy is compromised.

Could you heat a smaller space instead of your entire house? Maybe a closet? Or maybe some kind of see-through box with a Peltier plate in it? The guy who tested my samples five years ago used one of those plates for the samples. I don't know what he did with the VST itself. Where he lived it was sub-freezing that time of year so he surely had his house heated.

One advantage to weighing dehydrated samples -- the ambient temperature doesn't matter.