How to check SG without wasting too much brew?

Williams 728
Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

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

curious_nu

New Member
Joined
Sep 12, 2011
Messages
2
Reaction score
0
Location
Portland
The volume of the measuring cylinder I got with my first kit (back.. a couple of years ago, now) is something like a pint. I've found that the hydrometer really doesn't want to work unless the thing is nearly full (it just sinks to the bottom instead). I hate to blow through 3-4+ pints checking to see if fermentation is done. What's the trick to this? How can I use the least possible amount of liquid to check the SG?

Up 'til now I've just been waiting ~2 weeks and bottling, but my last couple of beers wound up as gushers, and I'm not sure if it was due to yeast that wasn't finished, or I just wound up adding too much priming sugar, so.. trying to check the SG from now on.
 
well first... your checking way too much 3-4pts is 48oz+
and the test tube holds about 3-4oz.....


you can buy a refractometer but once there is alcohol in it you need calculations to make it accurate

edit.....
missed the "pint sized test tube "
pics please?
a pint is 16oz id like to see what they gave you with your kit

if it is really that large buy a smaller "normal" test tube
 
I probably have the same measuring cylinder the op is using and have never used it as it would waste way too much beer. I use a little plastic cylinder that my floating thermometer came in to take gravity readings.
 
Just went to look for it and can't even find it now. -.- But it's DEFINITELY more than 4 ounces. I guess I'll just try and find a smaller one to use.
 
truebe said:
I probably have the same measuring cylinder the op is using and have never used it as it would waste way too much beer. I use a little plastic cylinder that my floating thermometer came in to take gravity readings.
Click to expand...

so then its a measuring cup and probably not ment for taking G readings

i used the tube my hydrom. came in until i spent the 3$ on a test tube
 
davis119 said:
so then its a measuring cup and probably not ment for taking G readings

i used the tube my hydrom. came in until i spent the 3$ on a test tube
Click to expand...

naw its advertised as a cylinder to hold wort for gravity measurements. There are no volume markings or anything. I'd imagine its used on the professional level and someone thought it would be fine for homebrewers as well.

the thing really is comically large. as soon as i got it in the mail i just laughed and facepalmed.
 
davis119 said:
i used the tube my hydrom. came in until i spent the 3$ on a test tube
Click to expand...

Second that. That tube only holds a few ozs, so you won't need to use more than a pint or so total throughout the brew. If that's still too much loss, go for a refractometer, it only takes a drop. Just remember, you need to use a conversion (chart or calc) to take an accurate reading once alcohol is present with a refractometer.
 
Hydrometers are a dinosaur.... Refractometer.... Period. Once you ferment plug it into any of the dozen available free calculators and you'll be spot on. I tested my fract side by side with my hydrometer for a few batches and it is spot on and takes 1 DROP to test with..... Don't wanna waste my tasty Nectar!!!
 
FredTheNuke said:
Hydrometers are a dinosaur.... Refractometer.... Period. Once you ferment plug it into any of the dozen available free calculators and you'll be spot on. I tested my fract side by side with my hydrometer for a few batches and it is spot on and takes 1 DROP to test with..... Don't wanna waste my tasty Nectar!!!
Click to expand...

I love my refractometer, but it's been useless for FG readings for me, even with correction software.

One hydrometer reading uses about 3 ounces of beer (in a normal sized test jar), which I drink. No loss, as far as I'm concerned.

If the FG is where I expected after a couple of weeks, and the beer is clear, it's done. I don't need to take three readings to know that.
 
Yooper said:
I love my refractometer, but it's been useless for FG readings for me, even with correction software.

One hydrometer reading uses about 3 ounces of beer (in a normal sized test jar), which I drink. No loss, as far as I'm concerned.

If the FG is where I expected after a couple of weeks, and the beer is clear, it's done. I don't need to take three readings to know that.
Click to expand...

That's right, man up and drink it!! I use a wine thief and only get as much as I need for the hydrometer. The two are close in diameter, so about 4oz does the trick. Then I drink it, zero waste.
 
My hydrometer jar is crazy big, takes at least 8 fluid oz to get a reading. So I don't use it often. The refractometer works well (corrected) but I'm not totally convinced it is completely accurate in an alcohol environment. It is a good tool to judge when fermentation is complete though.
 
I knew I should have worded that differently...we've been down this road before Yooper. Haha.

:drunk again
 
Yooper said:
Well, I don't often "man up". But I do drink my hydrometer samples.

:drunk:
Click to expand...

Nice!

Dan said:
My hydrometer jar is crazy big, takes at least 8 fluid oz to get a reading. So I don't use it often. The refractometer works well (corrected) but I'm not totally convinced it is completely accurate in an alcohol environment. It is a good tool to judge when fermentation is complete though.
Click to expand...

Gotta question for either one of you, just one then so I don't hijack. I've always used a hydro, but I'm thinking about a refractometer just cuz.... I like gadgets, I guess. What makes you say they're useless for FG even if you use a conversion? Just not accurate, like Dan says? Or something else? I don't wanna spend the $$ if my hydro (and drinking the samples) is a better way to go.
 
NordeastBrewer77 said:
Nice!



Gotta question for either one of you, just one then so I don't hijack. I've always used a hydro, but I'm thinking about a refractometer just cuz.... I like gadgets, I guess. What makes you say they're useless for FG even if you use a conversion? Just not accurate, like Dan says? Or something else? I don't wanna spend the $$ if my hydro (and drinking the samples) is a better way to go.
Click to expand...

For me, there are a couple of reasons. One, I don't even bother to check FG until I go to package the beer. It's usually long finished (I package at 2-3 weeks) and clear. I don't package cloudy beer, and if it's clear I'm pretty sure it's been finished for a while, But that's when I check the FG.

Even with conversion tables, the FG is just not the same as it is with a hydrometer. Pretty close, yes. But not the same. The whole point of checking the FG is to get a number, because I was already sure it was done (or stuck) and the gravity was not changing.

If someone is trying to "catch" a lager while still fermenting while the gravity is changing slightly, the refractometer might be useful. Or if someone is waiting for the SG to stop changing (even if inaccurate, a stable FG will mean the SG is not changing).

But for me, there is no useful purpose for an inaccurate FG reading.
 
To answer the question, the best way check FG without wasting beer: santitize your hydrometer, and then drop the hydrometer into the fermentation bucket. Bam. If there are too many bubbles on top of your beer preventing you from reading your hydrometer, it's not done fermenting.

I do it all the time. Just wash your hands and don't breathe when you open the lid :)
 
Drop a sanitized hydrometer right in the bucket and you'll have no loss. Might not be 100% but should get you within a point or two. You can do it with a carboy as well, but you probably won't be getting it back till you transfer.
 
allthingsgiant said:
To answer the question, the best way check FG without wasting beer: santitize your hydrometer, and then drop the hydrometer into the fermentation bucket. Bam. If there are too many bubbles on top of your beer preventing you from reading your hydrometer, it's not done fermenting.

I do it all the time. Just wash your hands and don't breathe when you open the lid :)
Click to expand...

Beat me to it!
 
Ya I dont throw the beer away after ive tested it, was wondering why no one had mentioned that approach.
 
Yooper said:
For me, there are a couple of reasons. One, I don't even bother to check FG until I go to package the beer. It's usually long finished (I package at 2-3 weeks) and clear. I don't package cloudy beer, and if it's clear I'm pretty sure it's been finished for a while, But that's when I check the FG.

Even with conversion tables, the FG is just not the same as it is with a hydrometer. Pretty close, yes. But not the same. The whole point of checking the FG is to get a number, because I was already sure it was done (or stuck) and the gravity was not changing.

If someone is trying to "catch" a lager while still fermenting while the gravity is changing slightly, the refractometer might be useful. Or if someone is waiting for the SG to stop changing (even if inaccurate, a stable FG will mean the SG is not changing).

But for me, there is no useful purpose for an inaccurate FG reading.
Click to expand...

Gotcha. Thanks Yoop. So it works to tell if FG is stable, but it's not accurate enough to gauge attenuation or ABV. I'm with you, I'd rather have an accurate FG reading. :mug:
 
A refractometer pays for itself after a few batches. You can test as many times as you want on brew day with only a tiny loss. Then wait until there is a clear sign of fermentation stopping (like a drop of the krausen layer) and measure with a hydrometer. I don't check gravity on every batch. When it's cold out, I just let it ride for 3 or 4 weeks and taste test before racking. I will test after a few days when the temp is warmer due to impatience though. Just the other day I checked my pliny clone fermenting in the low 70's to find it was still at 1.030 after 4 days. That's what I get.:cross:
 
I once made a very small batch of barley wine and didn't want to waste 250ml of fermenting beer on each SG check so I drew off (125ml) of wort and topped the rest up with plain water, took the SG and doubled the value.
not sure if the science behind this was ok but it saved me beer !
 
NordeastBrewer77 said:
Gotcha. Thanks Yoop. So it works to tell if FG is stable, but it's not accurate enough to gauge attenuation or ABV. I'm with you, I'd rather have an accurate FG reading. :mug:
Click to expand...

I don't know what most consider as "accurate".

What I have found is that for the nominal range between 1.035 or so and 1.055, the calculations are within the margin of error on either the hydrometer or the refractometer. +/- 0.001 typically. Once you start getting into the higher gravities, I find that the error increases (although it typically increases in a constant direction... meaning the refractometer corrections will over-estimate the FG. Not all refractometers are the same, so YMMV, but I have had great luck with mine and I am more than happy to be within a point or two of FG by simply using the refractometer.
 
I'm trying to think of a way to do your guy's hydrometer dunk method in a carboy. Can I just drop the sanitized hydrometer in on brew day and leave it there? That way I can check it whenever I want after krausen without having to open it.
 
truebe said:
I'm trying to think of a way to do your guy's hydrometer dunk method in a carboy. Can I just drop the sanitized hydrometer in on brew day and leave it there? That way I can check it whenever I want after krausen without having to open it.
Click to expand...

Krausen will stick to it and change the weight/balance of it.
 
what if you rocked it back and forth a little to bob it? and would that small amount of foam really be significant? Might be a pain if it made it hard to read though.
 
Yeah... I'm thinking wait till the krausen has subsided before dropping it in. That way, there won't be much foam and gunk on the top to interfere with the reading. You can leave it in there, but it may get hard to read and become inaccurate after foam accumulates.

I use buckets for primary and glass for secondary if needed. It's easy to check and retrieve from a bucket. When the primary is stable, I give it a couple more days then rack to secondary... no need for additional readings and I dry hop a lot, so a hydrometer with hops in the fermenter would cause problems.
 
Krausen doesn't always drop. I vote for drinking your samples after you buy a smaller test cylinder.
 
H-ost said:
Krausen doesn't always drop. I vote for drinking your samples after you buy a smaller test cylinder.
Click to expand...

Tell me about it! I use 1318 a lot, big time top cropper, seldom drops for me without encouragement. I have an ESB on it right now, FG's been stable for a few days, beer's clear.... just sitting between two layers of Boddington's dough. Reason #1 not to leave the hydro in there.... with yeasts like that, you may not even be able to find it in the krausen layer once the gravity lets it sink a bit. :mug:
 

Similar threads

Peebee
SG and Temperature Compensation
2
Replies
44
Views
2K
Peebee
Peebee
B
Terrible brew
Replies
25
Views
1K
Craiginthecorn
C
odie
how much saved yeast cake do you pitch or should you pitch ?
Replies
24
Views
3K
odie
odie
J
Time to transfer to secondary? to crawl space?
Replies
1
Views
527
Rish
R
RudeBooch
Tilt Hydrometer reading wrong SG wort
Replies
13
Views
1K
jtgoral
J

Latest posts

Back
Top