Altitude and the hydrometer

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kappclark

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I got my replacement hydrometer...

I was thinking - I live at abt 2,000' -- does my altitude affect the hydrometer reading ? If so, it can't be anything major, I wld imagine.

The instructions only mention adjustments for temperature...

I DO see that water boils at abt 208 now.. just think of all the propane I will save !
 
kappclark said:
I got my replacement hydrometer...

I was thinking - I live at abt 2,000' -- does my altitude affect the hydrometer reading ? If so, it can't be anything major, I wld imagine.

The instructions only mention adjustments for temperature...

I DO see that water boils at abt 208 now.. just think of all the propane I will save !

I've never made an altitude adjustment (nor have I ever heard it was necessary) and I live at 9100'. They hydrometer is just measuring density of the liquid and that shouldn't be affected by altitude.
 
It would kinda make sense there needs to be an adjustment. I'de just see what your starting waters SG is. Since water should be 1.000 on your hydro, take the + or - and adjust your readings against that.
 
Even if the reading is not exact, the formula for alcohol content will give the same results after tempature correction and the lack of reading changes will tell you your beer is done. That’s all that’s really important anyway.
 
I live at just above 4,000' MSL, and my hydrometer shows exactly 1.000 in distilled water at 60 degrees F.

I imagine that there is a VERY slight difference in liquid density at varying atmospheric pressures, but because liquid is not generally very compressible, the correction factor is probably imperceptible on the brewer's hydrometer scale.
 
I think its the fact that liquid doesn't really compress, so altitude doesn't have an effect on density like it does on boiling temperatures.
 
Thank You for the prompt feedback - I am a computer guy, not a chemist !

This all makes tons of sense - liquids don't compress, so atmospheric pressure should have little/no effect...

I will measure/calibrate the hydrometer at 60 degrees using water ....I hope it measures correctly...

(what happens when I don't get the perfect reading ?? (just kidding)

Now - may I use my well water (which is perfectly good), or distilled water ?

I wld think the well water, since it is that which I will be using to make this fantastic brew !

What a hobby for the type A !
 
kappclark said:
Now - may I use my well water (which is perfectly good), or distilled water ?

If your well water does not have off flavors you should be fine using it.
 
I think i read someplace that well water can actually be better for brewing than citys tap water.
 
if you like your well water use it. I think you can get water tests for $20 or so. This will tell you about your chemistry so you can adjust for different types of beer if you so choose. You will be better off to use distilled water if you want to try and calibrate your hydro though. The dissolved solids, salts etc. will alter your waters SG though not appreciably.
 
I have had very good results with the well water and brew ... I used to pre-boil the mixing water when doing partial boils - good results...then I stopped and results still good...VT is a wonderful place !

Now have big pot so no need to worry abt that..

I will get the distilled and measure @ 60 deg. And, just for kicks, I will measure using well water to see if there is a diff...

Thx for the replies !
 
The altitude will not have an effect large enough for you to see.

The hydrometer works by the bouyant force when it is in the liquid. The bouyant force of anything in a fliud is equal to the weight of the fliud displaced when the object is in the fluid. So when the density of the wort is greater, the hydrometer doesn't need to diplace as much liquid for the bouyant force to counter-act its weight due to gravity , so it will float higher in the water.

When the hydrometer is in air, it feels a bouyant force too, as air is a fliud. But it doesn't float in air because the air displaced by the hydrometer weighs much less than the hydrometer weighs, so gravity wins (it is the bouyant force in the atmosphere that makes hot air balloons float). If you pressurized the crap out of your garage then took a reading, the hydrometer should sit just slightly higher in the water due to the increased bouyant force on the half of the hydrometer that is sticking out of the water (don't try this experiment, your garage would explode before you could measure a difference).

But because water is about 800 times more dense that air, any slight change in air density should not be measurable, or of any importance to brewing.
 
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