Usefulness of a hydrometer

[Prunes]

Hello,

Just getting back into brewing, did a lot with dad back in the day, and have done my own apple cider a couple of years ago.

What is a hydrometer useful for other than estimating ABV, I see things on the net saying it can improve your beer, etc. but nothing ever seems to mention how to use it to improve your brew.

There is mention of working out of your fermentation is stuck, but does that happen if you control the environment of your fermentation correctly and wouldn't you notice? (short fermentation, lack yeast activity, etc).

Thanks in advance.

 

[H@wkeye!]

Welcome.

In a word, a hydrometer is an essential part of a homebrewers kit. I tried to make use of just a refractometer. Didnt work as refractometers don't really work accurately when alcohol is present. Anywho, there are multiple threads here about these topics.

A hydrometer is used to measure the specific gravity. The gravity changes depending on the sugar content of the wort. Basically when the yeast consumes the sugar during fermentation, the sugar content decreases and the alcohol content increases. The hydrometer tracks this. A hydrometer is essentially a tool.

 

[Drewgong]

Welcome back mate ensure your wort is at the temperature that your hydrometer is calibrated at. Or google hydrometer temperature correction.

 

[Prunes]

Ok so here is the point, what is it actually being used for, what are you changing based on the data collected?

 

[mr_wibble]

An hydrometer uses density to measure sugar concentration of the wort.
For example sake, say you make a wort that gives a reading of 1.050 AKA "1050".

You measure your starting gravity just before you pitch the yeast.
Then, sometime later, you take another reading.
Say after 2 weeks your reading is 1.010 - "1010" as the kids say.

You can say, "Aha! It's dropped by 40 points" (0.04 actually)
Obviously the yeast has converted this amount of sugar into alcohol + CO2 + etc.
Applying a formula, this allows you to estimate the alcohol contained in the beer.

But it also tells you other things. For example, if that second reading was 1.030, you could infer that the beer is not fermenting properly.

Also if you took a few measurements over a few days, and the gravity was within finishing range, and no longer changing, you could consider the fermentation finished.

 

[Prunes]

Thank you so it's effectively a data collection tool which is more accurate than using observation alone. Since we can see the fermentation start, watch it progress, taper down and finish using visual queues.

 

[Droopy Brew]

No do not rely on observation to determine if a beer is done or stalled etc.
A HYDROMETER IS A MUST.
While it wont improve your beer per se, it will allow you to understand if fermentation is done or not- which is an improvement I guess.
If you are getting back into it, don't take shortcuts. Cleanliness, temp control and proper measuring is all a prerequisite to make a decent beer regardless of your methods (K&K, AG etc). If you don't know your gravity, you will end up with bottle bombs at some stage.

 

[MHB]

Good for lots of other things to.
But first time something goes awry and you post a question, odds on first reply will be "what's your OG, what's it at now"
It is a very good diagnostic tool, provided you use it and keep a record of your readings.
Mark

 

[Rocker1986]

**** even after 6 years I still don't take shortcuts. Everything is properly cleaned, sanitised, fermentation temp control is used every batch and everything is measured, mash temp, OG, FG, yeast cell counts as best I can etc. Nothing ever goes wrong once the brew is in the fermenter, but the one time you slack off on something is likely the time it would go wrong.

I keg my beers now, so bottle bombs aren't a concern, but if the beer fails to reach the predicted FG or close enough to it, then it can alter the flavor as well. I took a 3 day sample from a fermenting pale ale yesterday and it was sitting at about 1.030 on the hydrometer. Smelt and tasted far too sweet at that stage (as I expected it would), though this will diminish as it ferments further towards target FG. However, if I didn't bother testing for FG in another couple of days and it ended up stalling there at 1.030 for some reason, it would be rather a disappointing beer if I'd simply figured it had finished and kegged it up.