Why do brewing hydrometers have no thermometer?

I work in oil and gas production and we use hydrometers frequently in our work. Our hydrometers have internal thermometers so that you can just take a gravity and temp at the same time. Womdering why the hydrometers you get from most brew places don't have them? Do yours?

Because you haven't started manufacturing them yet!

I've seen them- most online homebrew shops have them, I believe. I have a "stick on" thermometer on the outside of the fermenter to monitor fermentation temperature, so I don't need another way to measure temperature during the hydrometer reading.

my LHBS has them. I don't know what's wrong with yours??? Why don't you just take one from work?

So you are saying I should start carrying a Hydrometer/Thermometer combo?

Forrest

Austinhomebrew said:

So you are saying I should start carrying a Hydrometer/Thermometer combo?

Forrest

Click to expand...

YES! That is exactly what we are saying

I used to have one, but the thermometer got jacked up when I put it in 150 ish deg wort. The SWMBO broke that one a month ago. I prefer using a digital thermo anyways...

i have a stick on the glass test jar. so far so good.

Northern Brewer carries them.

Thermohydrometer

ATC, ATC. After you break the second or third hydrometer, you realize you could have bought a $24 Ebay refracto.

B

Why don't you just take one from work?

Click to expand...

SHHHHHHHHH!!!!!!!!!! LOL!!

zman said:

YES! That is exactly what we are saying

Click to expand...

I agree. I have to say that as a person new to this hobby I grew to really hate the standard hydrometer that comes with every kit. To me it's extremely misleading to tell new people that the basic hydrometer is good enough to take readings. There is so much new stuff to try and take in that I think it's nice to try and make it easier, but a new brewer will eventually realize to get accurate readings they have to also know the temperature and then adjust accordingly (assuming they went through the trouble to calibrate the hyrdometer at 60 degrees in the first place).

Thermohydrometers work great, just have to keep the samples below 120°F.... I think I use it more than any of my other sugar measuring tools.

I check the sparge runnings with a refractometer to gauge the sugar at 10minute intervals (I find taking samples and cooling them constantly them an annoying task).
I usually use my thermohydrometer for OG and testing the wort during fermentation; I sometime use the refractometer to verify.
I use a finishing hydrometer once the FG is under 1.020

Realistically, the correction for the beers I make, at the temperatures I ferment them will run less than a point.

This morning it struck me that perhaps we should use hydrometers that have the same coefficient of volumetric thermal expansion as water, so we don't have to adjust the readings for temperature.

A quick look at a table of the coefficient of expansion of different plastics identified polycarbonate as the one that matches water very closely.

So now we need to figure out how to make a polycarbonate hydrometer!

gturner6ppc said:

This morning it struck me that perhaps we should use hydrometers that have the same coefficient of volumetric thermal expansion as water, so we don't have to adjust the readings for temperature.

A quick look at a table of the coefficient of expansion of different plastics identified polycarbonate as the one that matches water very closely.

So now we need to figure out how to make a polycarbonate hydrometer!

Click to expand...

That might work if the hydrometer is solid polycarbonate. If it's hollow like most of the glass instruments I've seen the air inside has a different temperature coefficient. (But would it matter? Its volume is constrained by the tube. But the tube can expand or shrink. Ow, my head hurts.)

At any rate, the hydrometer would have to soak in the sample for a while to equalize temperatures. But it sound like some experimentation is in order.

Dave

Austinhomebrew said:

So you are saying I should start carrying a Hydrometer/Thermometer combo?

Forrest

Click to expand...

Yes!!!!!!!!!!!