• Please visit and share your knowledge at our sister communities:
  • If you have not, please join our official Homebrewing Facebook Group!

    Homebrewing Facebook Group

How to check specific gravity?

Homebrew Talk

Help Support Homebrew Talk:

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

kombat

Well-Known Member
Joined
Oct 17, 2009
Messages
5,681
Reaction score
2,190
Location
Ottawa, Ontario, Canada
I've got a quick, practical question regarding checking the specific gravity during secondary fermentation.

My beer is in the carboy, and I want to start checking the specific gravity. I know I need to siphon some out and check it with my specific gravity meter (the little thermometer-looking thing, inside the tall, cylindrical tube). My question is, how do I get some beer out of the carboy without contaminating the whole batch?

Do I really sterilize my whole autosiphon and pull out a bunch of beer, just to get a little bit to test? Isn't that a little wasteful? How do you guys get enough out to check the SG without sterilizing a whole autosiphon and extracting more beer than necessary (thus wasting some)?
 
Use a beer or wine thief, or a turkey baster. Only take out enough to mostly fill your test jar (a tall, skinny cylinder that should have come in your brewing kit, assuming you went with a kit). You should only need about a cup or so - and the tool you're talking about is a hydrometer!
 
Sterilize your racking cane. Stick it in your carboy, then hold your thumb over the other end and pull it out. Do this a couple of times and you should have enough for a hydro reading. I have a wine theif, which makes hydrometer samples from a carboy much easier.
 
What stratslinger said. As far as wasting goes, as long as everything has been sanitized properly, you can gently pour most of the sample back in and leave a little for a taste test.
 
You dont need to bust out your racking cane for a gravity reading. Break out your hydrometer (tall cylinder thermometer looking thing), and a turkey baster. Clean, and sanitize your baster and push it deep in the middle ofyour fermenter. Fill up the hydrometer tube about 3/4 full or so and drop the thermometer in. Measure your reading and write it down. Then drink the the sample and take notes of it as well. Its not a waste unless you pour it down the drain. Use it as a tool to know how your beer is coming along. Relax dont worry have a hydrometer brew.
 
Sanitize some tubing, dip it in your carboy, put your thumb over the end and pull it out. Do this once for a refractometer reading or several times for a hydrometer reading. And DO NOT POUR IT BACK IN
 
This is what I use, and it works with both buckets and carboys. And probably FV's whatever the heck those are....

I replaced the plastic one a year ago with an extra long stainless baster from a kitchen ware store and it is awesome. But the plastic one from any grocery store works fine.

turkeybastera.jpg


And

75862_451283689066_620469066_5427695_1841038_n.jpg


Here's what I do....

1) With a spray bottle filled with starsan I spray the lid of my bucket, or the mouth of the carboy, including the bung. Then I spray my turkey baster inside and out with sanitize (or dunking it in a container of sanitizer).

2) Open fermenter.

3) Draw Sample

4) fill sample jar (usualy 2-3 turky baster draws

5)Spray bung or lid with sanitizer again

6) Close lid or bung

6) add hydrometer and take reading

It is less than 30 seconds from the time the lid is removed until it is closed again. More like 15 if you ask me.

Probably less if you have help. And unless a bird flies in your place and lets go with some poop, you should be okay.

ANd then you drink the sample....don't pour it back in....
 
I don't pour it back in either. I think a lot of us don't take many readings, so if you're worried about beer loss, maybe that's an issue.
 
I'm not saying to violently splash it in or anything, just very gently or use the theif/baster to put it back in. I've never had any problems doing this.

I'm saying don't pour it back in at all. Your are risking infection and wild yeast of your whole batch to try to save a few ounces of beer.
 
I'm saying don't pour it back in at all. Your are risking infection and wild yeast of your whole batch to try to save a few ounces of beer.

+1....There's no point in risking infection by pouring it back it. All you need is some airborn micro organisms to come in contact with it as it's sitting in the test jar, or even just pouring it through space back into the fermenter.

Better to dink it to get a taste of what's happening. Just don't panic if it taste funny....It's still on it's journey.
 
Fair enough. Never had any problems before but I guess it would only take 1 6 gallon batch of ruined beer to change my mind in a hurry. Lesson learned, I'll behave from now on :mug:
 
Hydrometer help! So I have brewed 4 batches of beer now, 2 all grain and 2 extract (not a fan of the extract, got the kit as a gift). I got a new Hydrometer but every reading I have taken has not worked. The hydrometer sinks to the bottom of the test tube and bottoms out. The beer definitely has alcohol in it (after a few, you feel it). Why is this happening? Is it possible I have a faulty hydrometer? I'm getting annoyed with not getting any proper readings! This happens when taking og reading and sg reading.
 
PapaRib - What is the range of your hydrometer and when it bottoms out, what gravity is at the top? You could have gotten a hydrometer meant for something else with a different scale. If you put it in a test tube with water, what does it read?
 
Hydrometer help! So I have brewed 4 batches of beer now, 2 all grain and 2 extract (not a fan of the extract, got the kit as a gift). I got a new Hydrometer but every reading I have taken has not worked. The hydrometer sinks to the bottom of the test tube and bottoms out. The beer definitely has alcohol in it (after a few, you feel it). Why is this happening? Is it possible I have a faulty hydrometer? I'm getting annoyed with not getting any proper readings! This happens when taking og reading and sg reading.

Is your test tube taller than your hydrometer?
 
Hydrometer help! So I have brewed 4 batches of beer now, 2 all grain and 2 extract (not a fan of the extract, got the kit as a gift). I got a new Hydrometer but every reading I have taken has not worked. The hydrometer sinks to the bottom of the test tube and bottoms out. The beer definitely has alcohol in it (after a few, you feel it). Why is this happening? Is it possible I have a faulty hydrometer? I'm getting annoyed with not getting any proper readings! This happens when taking og reading and sg reading.

After reading the above post...

I think you might be on to something there. I bet my test tube is too small. It's a 1000 ml graduated cylinder.

...and then this one I think that you should take hydrometer reading before consuming your beer. :drunk:
 
I think you might be on to something there. I bet my test tube is too small. It's a 1000 ml graduated cylinder.

So wait - you have basically a 1L graduated cylinder... How tall is it? If it's tall and skinny, that should be WAY more than sufficient to get a good gravity reading. I think my hydrometer test jar only holds a cup, maybe a cup and a half of fluid - definitely less than 1L! Now, if that 1L cylinder is relatively short and wide, well then you could certainly have a problem.
 
One liter is in fact massive. My hydrometer test tube holds 6 ounces, I think. I used to use the plastic tube it came in, which held 4 ounces.

You're not filling it with 30+ ounces of beer when you check the sample, are you?
 
Wow, thanks for all the replies, guys. It turns out my wife actually has a wine thief, so I tried using that first. However, it was only transferring such a small amount each time that it would have taken all night to get enough for a reading.

So I used the other tip, sterilized my racking cane, and dipped it. This worked better, although each time I took it out, it "leaked" a little out the end, even though I had my finger tightly over the other end. It made a little bit of a mess, but it got the job done.

Anyway, I eventually got enough for a reading. It looks like 1.006. Does that sound right? This is a batch I started 8 days ago, and moved to secondary on Saturday. EDIT: It's a Canadian Blonde, from a malt extract kit, if that matters.
 
Anyway, I eventually got enough for a reading. It looks like 1.006. Does that sound right? This is a batch I started 8 days ago, and moved to secondary on Saturday. EDIT: It's a Canadian Blonde, from a malt extract kit, if that matters.

Sounds right to me except you moved it to a secondary way too soon
 
And again - if you're really using a 1L graduated cylinder, get a different test jar! You're throwing away far too much beer for a hydrometer test this way. With a properly sized jar, a wine thief should fill it sufficiently in 2 or 3 quick passes.

That said, I'd expect a "properly sized" wine thief to do the trick quicker than a racking cane - they should be roughly the same length, but the thief should be bigger around. Maybe the thief your wife has and the thief we're suggesting are two different things?

Check this out
 
Sorry guys, that was a typo on my part. Good to see so many comments though. It's a 100 ml glass cylinder. The top is about a half inch shy of the top of the hydrometer. A now obvious mistake on my part, I think it's just too small of a test tube.
 
I use a turkey baster. Works quite well, and is real easy to sanitize.

And you only really need to take 2 readings, not 3.

Take one on say, Monday...if it reads the same gravity when you take a reading on Friday, you're good to go.
 
FYI .... I have a thief and the day I first used it i said to myself " this thing is going to take 10 dunks to fill". Then I realized I wasn't letting the beer equalize inside the thief. There is a small hole that the beer has to fill up into, to get your sample. If you stick it in the carboy or what have you and just wait for 5 or 10 seconds, it will fill up to as high as you have it stuck in. I was sticking it in and immediately capping my thumb over the hole on the top. There's not enough time for the beer to fill the thief this way. There's a 1/8th inch hole filling a 1 inch tube!
 
For those of you with buckets:

I used to use a thief or turkey baster, but sometimes I would have to double dip to get a big enough hydrometer sample. Then I realized I could just use one of the many coffee mugs in my cabinets. Easy to sanitize (no problem just boiling it in water if necessary), and very easy to get the sample. I just dip it in and fill it about 2/3. Enough for a hydrometer sample every time.
 
Back
Top