I am currently looking for a better way to monitor brewing progress than to have to pop out my syphon every few days and syphon it out for a hydrometer reading.

Now I am currently looking at using a hydrometer for salt water fish tanks to use inside a transparent fermentation vessel.

Has anyone tried this? Any recommendations?

  • A Brix refractometer is a cheap, effective way to take a gravity reading without withdrawing a large sample of fermenting beer. Dec 13, 2013 at 18:52
  • 2
    Be aware that a refractometer is inaccurate once fermentation begins. It can still be useful to see that fermentation is still progressing, but it won't give you a correct final gravity.
    – jalynn2
    Dec 17, 2013 at 18:50

2 Answers 2


If the issue is not wanting to pull excessive volume of beer/wort for testing, get a brix refractometer — they're QUITE economical (averaging $20-25) and only pull a small dropper's worth. When you use a reputable calculator for converting brix readings to factor in alcohol, it can be accurate within .005, which frankly is good enough for most home brewing endeavors.

The Brix calculator from Northern Brewer does a fine job as does Sean Terril's.

I'm not sure how good of results an aquarium hydrometer is going to produce since it has a specific purpose (measuring salinity instead of weight of sugars left in solution) and is not necessarily calibrated for measuring beverages like beer, wine, mead, etc. You may wish to do a side-by-side comparison over the course of three or four beers to test for yourself its level of accuracy. But I'm inclined to think it won't work.


I'm not sure when it will be readily available, but you can check out the BeerBug - http://www.thebeerbug.com/.

It uses Bluetooth, and gives continuous data to graph your fermentation progress.

I haven't tried the salt water hydrometer, but as long is it can be sanitized and will fit in your fermenter, then give it a try!

  • I am a kickstarter supporter of this. I believe they are shipping the bluetooth version to supporters now. I am waiting for the wifi version. It's pretty pricey (considering that a regular hydrometer is just a few bucks), but I am hoping it works well.
    – jalynn2
    Dec 17, 2013 at 18:48

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.