Everyone knows hydrometers are fragile....

[freisste]

But just to drive the point home and remind everybody:

I was making a starter for an Oktoberfest (way behind schedule as I would have liked to get this to the lagering stage before my basement warms up) and decided to check the gravity of an IPA I have fermenting. Grabbed the hydrometer and put it in the bucket of starsan. Grabbed it by the end and it shattered between my thumb and index finger.

Maybe a defect in the hydrometer or maybe I don't know my own strength, but damn that is some thin glass. So long story short, I'm down to one working hydrometer and one un-cut thumb.

Be careful!

 

[knuckleheadbrewing]

I've had them break the same way....I swear I didn't grab it that hard.....LOL

 

[bernardsmith]

why are hydrometers made of glass? If the issue is only how high or low it floats in a liquid then why cannot we make a hydrometer out of other material that has a similar density to weighted glass and which would be as easy to clean and sanitize as glass and which would be rather less breakable.

 

[giant]

My first hydrometer broke as I laid it on my counter just seconds after opening it. Needless to say, I was pissed.

 

[rodwha]

Mine haven't broken quite that easily, but I do keep spare hydrometers and thermometers on hand just because of that.

 

[Sbarnard80]

Had my first break a few weeks ago. Luckily I had a backup and will always have one.

 

[DaNewf]

I've often wondered why plastic hydrometers haven't caught on any better than they have. I got one with my Cooper's DIY setup when I started brewing. That's over two years ago and it still works fine even though I wasn't particularly gentle with it. It reads four points low (1.010 instead of 1.014 for instance) but once you allow for that you are good to go.

 

[k1ngl1ves]

I've broken a hydrometer by just looking at it... Lol!

 

[kh54s10]

I've often wondered why plastic hydrometers haven't caught on any better than they have. I got one with my Cooper's DIY setup when I started brewing. That's over two years ago and it still works fine even though I wasn't particularly gentle with it. It reads four points low (1.010 instead of 1.014 for instance) but once you allow for that you are good to go.

I think that is the reason. I read that they are very difficult to manufacture with any real degree of consistency or accuracy. If they had to test and adjust every one they would be very expensive.

 

[Setesh]

why are hydrometers made of glass? If the issue is only how high or low it floats in a liquid then why cannot we make a hydrometer out of other material that has a similar density to weighted glass and which would be as easy to clean and sanitize as glass and which would be rather less breakable.

Actually it is very hard, if not impossible, to sanitize plastic after it has been scratched, which happens very easily. Glass is less susceptible to this problem. As long as you are discarding the sample this really isn't an issue though.

 

[Beernik]

Believe it or not, I've had one roll off my picnic table, land point down on my concrete driveway, and not even chip.

I guess after breaking dozens, I deserved to get lucky once.

 

[rodwha]

I sanitize mine and just toss it in the fermentor. If a wine thief can be sanitized well enough to stick in there a hydrometer ought to be as well.

But I also don't check the gravity reading until bottling day, and I typically give my beer 4 weeks.

 

[kh54s10]

I used my first hydrometer for more than 2 years. Then I had a sample in the tube and set it behind my Better Bottle. When removing the autosiphon the tubing caught the tube and sent it flying.

I also use a refractometer and my 2nd hydrometer. Three years in the hobby this July 1.

 

[LovesIPA]

I haven't broken a hydrometer yet. I usually set it on a towel to dry and then put it back in the container. I use a plastic 100ml graduated cylinder but I never return samples so infection isn't an issue. 54 batches so far.

 

[Setesh]

Believe it or not, I've had one roll off my picnic table, land point down on my concrete driveway, and not even chip.

I guess after breaking dozens, I deserved to get lucky once.

Glass is an odd thing. It is an amorphous solid, meaning that it's component molecules form random connections. This makes it respond similarly to stress in every direction (on every plane). BUT, it's mechanical strength is dependent on it's thickness and whether or not it is under compression. The thickened end of a glass hydrometer is it's strongest part. The top tube, however, is very thin so it will break with far less force than the bulb end. While it may take a good whack on the bulb end, just a small amount of force will break the tube end.

Tempering glass increases the strength dramatically by opposing the forces of the inner core and outer wall. A great example of the strength of glass under compression is Prince Rupert's drop:

[ame]https://www.youtube.com/watch?v=6V2eCFsDkK0[/ame]

 

[rodwha]

Crazy!

 

[Munchkin]

that was a very interesting video, thanks!