Fixing hydrometer?

[natmartin]

I think my hydrometer needs to be recalibrated.

If I drop it into plain tap water, it measures 0.997- 0.998 instead of 1.000.

I know that 1.000 is for distilled, but should tap water be that far off? And if anything, wouldn't tap water be a higher SG than distilled?

I guess the little piece of paper inside the hydrometer slipped. Is there any way to get that little piece of paper to move? Or should I just by a new hydrometer next time I get ingredients?

In the meantime, I'm just adding .002 to any measurements I take.

 

[LuiInIdaho]

To recalibrate your hydrometer, get some distilled water. Measure the density of the water at 60 degrees Farenheit (assuming that this is the temperatue for which the hydrometer is calibrated). Take your measurement. You know that at 60 degrees the hydrometer should be reading 1.000. If it is readying 0.997 you know that you need to make a manual adjustment and add 0.003 points to your reading when measuring the density of beer. Your hydrometer is now calibrated.

 

[natmartin]

How important is the distilled part? Does tap water vs distilled water really have that big of a difference?

Also, I know how to calibrate it... I was wondering more if there was any way to move the paper inside the hydrometer so that it reads correctly.

 

[damnitbeavis]

How important is the distilled part? Does tap water vs distilled water really have that big of a difference?

Also, I know how to calibrate it... I was wondering more if there was any way to move the paper inside the hydrometer so that it reads correctly.

I think that ions (removed by distillation from tap water) don't affect specific gravity, only non-ionizing solutes, like sugar, for example. Your tap water should do fine, but I may be talking out my ass.

 

[Catt22]

How important is the distilled part? Does tap water vs distilled water really have that big of a difference?

Also, I know how to calibrate it... I was wondering more if there was any way to move the paper inside the hydrometer so that it reads correctly.

Tap water will work just fine unless, of course, there is something seriously wrong with your tap water. I cannot detect any difference in the readings between my tap water and distilled with either a hydrometer or a refractometer.

There is a slim chance that you may be able to shift the paper scale by tapping the hydrometer on a hard surface, however, if it's that easy to get it to move I wouldn't trust it to stay put. You also risk breaking the hydrometer when doing this. I would just apply the offset and live with it or get another instrument. FYI, I bought one of these that I like a lot:

http://www.williamsbrewing.com/PRECISION-SPECIFIC-GRAVITY-P539C74.aspx

The scale gradations are wider and much easier to read than the standard type. It's a few bucks more, but well worth the extra cost IMO.

 

[natmartin]

FYI, I bought one of these that I like a lot:

http://www.williamsbrewing.com/PRECISION-SPECIFIC-GRAVITY-P539C74.aspx

The scale gradations are wider and much easier to read than the standard type. It's a few bucks more, but well worth the extra cost IMO.

That's actually the one I have. I do like it a lot. Thanks for the advice everyone!

 

[subliminalurge]

Tap water will work just fine unless, of course, there is something seriously wrong with your tap water.

There is, in fact, some seriously funky tap water out there. I just lived in a town for two years where the tap water was not only undrinkable, but it made me cringe to know that my dishes were being washed in it. Every time anyone took a shower the house smelled like chlorine and sulfur for a good hour.

That being said, basic hydrometers are cheap. If the one you have has the paper inside, then you have the cheap one. Just pop the 7 bucks and replace it. Your time is worth more than the effort it would take to get the old one back to a trustworthy state.

 

[Catt22]

There is, in fact, some seriously funky tap water out there. I just lived in a town for two years where the tap water was not only undrinkable, but it made me cringe to know that my dishes were being washed in it. Every time anyone took a shower the house smelled like chlorine and sulfur for a good hour.

That being said, basic hydrometers are cheap. If the one you have has the paper inside, then you have the cheap one. Just pop the 7 bucks and replace it. Your time is worth more than the effort it would take to get the old one back to a trustworthy state.

Every hydrometer I have ever seen or used has been the type with a paper type scale inside. I have four different hydrometers and all have the paper type scale.

I'm sure there are locations where the tap water is screwed up, but I seriousluy doubt that it would contain enough soluables to register on our relatively crude instruments. Water that bad probably doesn't meet the federal drinking water standards either. What town was that in?

 

[Catt22]

That's actually the one I have. I do like it a lot. Thanks for the advice everyone!

Are you certain that you are reading it properly? Top of meniscus or liquid level? That could be the problem right there.

 

[natmartin]

Are you certain that you are reading it properly? Top of meniscus or liquid level? That could be the problem right there.

I could be off by .001 due to the meniscus... it's hard to tell, I honestly don't see much of a meniscus.

But the 1.000 mark is certainly several lines below the water, there's no question of that.

My water is hard, but it's not horrible. It's about 10% hetch-hetchy water, and 90% ground water. I miss the 100% hetch-hetchy water in SF, that was some amazing water. So soft, so drinkable.

We're only 20 miles from SF, but this water is much harder.

 

[ACbrewer]

I'm not sure that the amount of disolved minerals in your water will matter, esp if you use that water for your beer.

An interesting experiment would be to take some salt and super saturate some water and take a hydro reading before and after the salt. This would answer 'does it affect gravity'.... Of course at this point it is like 10% salt, and tap water at worst I think is measuring in the parts per million range, not parts per hundred.

 

[Catt22]

I do agree that it is very strange that the reading is less than 1.000. Distilled water is cheap and readily available, so it might be worth the trouble to test again with some. I would expect it to me much closer than three points off. That's a lot.