Hydrometer reading confusion

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Dave 666

Regular.
Joined
Jun 5, 2018
Messages
347
Reaction score
66
So, having owned this hydrometer for more years than I care to remember I've never got round to working out the reading meaning. Fast forwards 20 odd years I try again with my new home brew beer kit.

As per the kit instructions I take 2 readings between stirs just before adding the yeast and first ensuring both reading were the same, which they were at about 1042. Yet that means nothing to me except I originally read it as meaning 6.5-7.0% abv for a stated 6.0 abv kit filled to the full 23 litres and no additional ingredients. But I'm thinking I might be very wrong as the hydrometer was in the bucket and possibly affected by surface bubbles despite identical reading between stirs prior to adding the yeast.

So any advice as I can't work out if a starting reading of 1042 indicates I might end up with a far weaker abv brew than originally thought?.
 
1.042 would certainly be much weaker than a 6% beer OG.

You now need to ferment your kit and take a reading when it’s finished (probably in about 2 weeks).

The OG (1.042) and the FG (which you will measure in 2 weeks time) need to be inputted into an AbV calculator and this will tell you the strength of the beer!
 
What technique do you use? Did you spin the hydrometer (as per instructions) to rid it of bubbles adhering to it? Also if you had surface bubbles and it’s inside a big vessel, how can you ‘sight’ it?

Deffo not being clever as I’ve only just returned to brewing after years and have forgot most of what I knew.

Anyhow, was 1042 above the bubbles? Maybe true reading is higher?



Sent from my iPhone using Tapatalk Pro
 
I know all this home brewing is more about the final taste and flavour (in other words a successful brew) than the final abv. But I can't help thinking I've gone wrong so early on as I bought purely on the offered sample drink over the abv and only then realised I'd bought a strong abv kit stated as a 6.0 %. But non the less thinking the initial reading might not follow the sample or abv claimed to give the same tasting brew at all?.

But no, a basic mistake in not spinning the hydrometer to rid it of bubbles in the bucket (where the reading was taken). I took the reading as slightly below the bubbles as being 1042 as obviously top of bubbles was a few mm's above the liquid surface. Maybe more a case of a false reading as contact with the bubbles would likely mean a level of external forces affecting the buoyancy to give a true reading?.
 
I know all this home brewing is more about the final taste and flavour (in other words a successful brew) than the final abv. But I can't help thinking I've gone wrong so early on as I bought purely on the offered sample drink over the abv and only then realised I'd bought a strong abv kit stated as a 6.0 %. But non the less thinking the initial reading might not follow the sample or abv claimed to give the same tasting brew at all?.

But no, a basic mistake in not spinning the hydrometer to rid it of bubbles in the bucket (where the reading was taken). I took the reading as slightly below the bubbles as being 1042 as obviously top of bubbles was a few mm's above the liquid surface. Maybe more a case of a false reading as contact with the bubbles would likely mean a level of external forces affecting the buoyancy to give a true reading?.

The best thing you can do is get a trial jar and a turkey baster from Wilco’s sanitize and rinse them and get some of the wort from the bucket in the jar and measure without the foam. Then you’ll know.


Sent from my iPhone using Tapatalk
 
The best thing you can do is get a trial jar and a turkey baster from Wilco’s sanitize and rinse them and get some of the wort from the bucket in the jar and measure without the foam. Then you’ll know.


Sent from my iPhone using Tapatalk

I agree with this, but it's less of an infection risk if you draw off wort/beer before putting anything in it.
 
Last edited:
Well I'm guessing the chance to retest has gone seeing as I woke up this morning to find the bucket having become very active with the airlock in place. Added to that work prevented me getting the trial jar today and not able to till tomorrow afternoon at the very earliest now. So any reading I might take now anyway would be just as inaccurate at the first I'm feeling.

But in all honesty, I don't really want to take the lid off the bucket unless it's absolutely necessary due to the risk of infection. As I can live with an inaccurate starting reading more than the risk of infection, even if a small risk.

Another factor (and of cause I'll learn and not repeat it twice) affecting the starting reading apart from the bubbles round the hydrometer would have been the temperature. Because as said the stick on thermometer doesn't seem to work for some reason so I had no accurate temperature reading either. If anything I'd guess the temp would likely have been a little higher than it probably should have been and I assume that would also affect an accurate reading?. So it really will be a bit of pot luck as I'm feeling I just can't rely of the reading at all.
 
I make wine not beer but the principle is the same. I always measure by putting the hydrometer in the barrel and giving it a little spin. If your going to draw of a sample to put in a trial jar the infection risk is the same as your still putting your turkey baster in to the wine and a glass hydrometer is easy to sterilise with a bit of isopropyl alcohol.

I would also recommend getting a refractometer as you can use this in conjunction with a hydrometer to get the ABV after ferment has finished (I have the formula if anyone wants it).
 

Latest posts

Back
Top