# What's the full volume of "3 gallon" carboy?



## whackfol (Dec 2, 2019)

Anyone know with some degree of accuracy what the volume of a "3 gallon" carboy is to the bottom of the spout? I'm fine with liters or gallons. 

Alternatively, do you know the liter volume printed on the bottom of the "3 gallon" carboy and what height they are measured to on the carboy?

I have most of my different carboys graduated with volume markings but can't seem to find a 3G with markings.


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## BernardSmith (Dec 2, 2019)

I am not sure the answer but what you may want to do is simply fill up three 1 gallon carboys and mark the 3 gallon vessel at the 3 gallon height. My sense is that the measure is at the height of the shoulder. That, by the way, is a good reason to always make far more wine or mead than the nominal amount you intend to make. Those nominal amounts are always smaller than the amount you need to fill a carboy so that there is little or no headroom.


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## cmason1957 (Dec 2, 2019)

You are going to have to figure this one out yourself. I am firmly convinced that every carboy I have is slightly to somewhat different in what it holds. My solution is the same always make a bit more than what I think I need.


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## jburtner (Dec 2, 2019)

+1 on making extra for top up. Through various craigslist carboy purchases i’ve ended up with different manufacturers versions of 3g, 5g, and 6g carboys and they’re all slightly different geometry. I also have plenty 1g and 1/2g jugs for storing top-up as well as 750’s and 375’s. 

I’m making much better effort now to keep it all topped up with absolute minimal headspace even though I also use headspace eliminators on the carboys. 

Cheers!
Johann


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## whackfol (Dec 2, 2019)

Thanks for your effort. I found my reference carboy.

FWIW: Italian carboy, 3 gallon on box, 11.4L in mold, 11L just above shoulder, and 11.75L 2 inches from top. Not sure where they measured the 11.4L


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## NorCal (Dec 2, 2019)

I've racked from one 5 gallon carboy to another and had it overflow by a significant amount. They vary within an few % manufacturer to manufacturer.


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## whackfol (Dec 3, 2019)

Norcal, agreed. It has been a while since I used carboys and I wanted to make an SO2 addition. I could not find the reference one for 3G and could not read the bottom with the carboy full. Just knowing what the manufacturer considered the "3 gallon" to hold from the mold was all I needed. Being off by 5% or so would not have affected this first SO2 addition.


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## Rocky (Dec 3, 2019)

I find that all carboys differ slightly, even ones that appear "identical."


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## mainshipfred (Dec 3, 2019)

I don't think I have a single carboy that holds the same amount of wine. Some vary way more than others.


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## Scooter68 (Dec 5, 2019)

I realized the same thing - Different capacities - This past spring. Sadly I haven't marked the carboys to identify the higher vs lower volume ones. So each racking time is an adventure - Befuddling sometimes when you worry about the lost volume and there isn't any, OR You should have no significant volume lost but suddenly it doesn't quite make it up to the narrow part of the neck and yet the amount left behind is only 3-4 oz.

Obviously quality control and 'truth in packaging' is not applied to carboys.

(Using 3 gallon carboys)


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## cmason1957 (Dec 5, 2019)

Scooter68 said:


> I realized the same thing - Different capacities - This past spring. Sadly I haven't marked the carboys to identify the higher vs lower volume ones. So each racking time is an adventure - Befuddling sometimes when you worry about the lost volume and there isn't any, OR You should have no significant volume lost but suddenly it doesn't quite make it up to the narrow part of the neck and yet the amount left behind is only 3-4 oz.
> 
> Obviously quality control and 'truth in packaging' is not applied to carboys.
> 
> (Using 3 gallon carboys)



I'm not sure it is a quality control or 'truth in packaging' issue, but more of a blown glass issue. They are probably made on a glass blowing machine and not by hand, but even with a machine, I wonder how much variation there is. Certainly if they were by home, then there would be no consistent sizing.

If you need exact amounts, you probably have to use all plastic, they are made in a mold and are probably all the same.


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## stickman (Dec 5, 2019)

Agree with @cmason1957 the glass blowing machine uses a mold, but that only gauges the outside diameter of the carboy, the glass thickness varies to some extent, so the inside diameter is less reliable. I'm sure there is a host of variables associated with how the machine is operated that determines the repeatability. Who's on shift today.......


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## Rocky (Dec 5, 2019)

Well, mathematically and in the absolute sense, there are no two vessels in the World that have the same volume.


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## cmason1957 (Dec 5, 2019)

But, I would imagine that if you take the average of the volumetric deviations for the plastic it will be significantly smaller than the same measurement for the glass. I'm sure they have an allowable tolerance.


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## Scooter68 (Dec 6, 2019)

cmason1957 said:


> I'm not sure it is a quality control or 'truth in packaging' issue, but more of a blown glass issue. They are probably made on a glass blowing machine and not by hand, but even with a machine, I wonder how much variation there is. Certainly if they were by home, then there would be no consistent sizing.
> 
> If you need exact amounts, you probably have to use all plastic, they are made in a mold and are probably all the same.



Guess I wonder about why other glass containers don't vary that much in volume or do they? Do wine bottles vary but we just don't notice because their volume isn't that much anyway? Are they made differently. Really wondering about that - I don't know why the methods of production would be that different. That's why I wonder if it comes down to the fact that nobody is really requiring that those carboys be that accurate in volume. Simply because they aren't sold with anything in them whereas wine bottles are typically going to be sold at some point with customer expecting an exact volume.


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## cmason1957 (Dec 6, 2019)

Just guessing, but size issue?? as in a 6 gallon carboy is 23 Liters (more or less), so maybe 24 times as large as a 750 ml bottle. Or maybe it is (as you pointed out) someone cares did I really get 750 Ml of wine, liquor, etc. whereas we as winemakers have little expectation that our 6 gallon carboys are really 23 liters. We need a glass manufacturers rep to weigh in, instead of a silly computer programmer who can only count 0 and 1.


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## Scooter68 (Dec 7, 2019)

BOTTOM LINE FIRST - The volume difference between my 3 gallon carboys is as much as *10 ounces.*
Let me explain what I did to get to that number. 
Today I racked 3 three gallon batches from/to "3 Gallon" carboys and here's what I found. (Batches in order were Elderberry, Mango/Pineapple, and Peach)
Each time I racked into a freshly cleaned carboy.
The first rack was into one of my spare 3 gallon carboys. (Container A for Comparison)
After racking I dumped out the sediment loaded wine that was not racked, Cleaned that carboy, then racked the next batch into the freshly washed and sanitized carboy I had just emptied.\
1) Elderberry batch (Carboy B) racking went fine - The clean spare carboy (Container A) was filled to within 1 1/2 " of the top. Left behind (In Container B)was approximately 6 oz of wine with sediment. I actually took 4 ozs of that as our sample for that batch and then dumped the other 2 oz down the drain. Note No topping off the carboy racked into so it was at least 6oz lower capacity.

2) Mango/Pineapple batch (Container C) rack into newly cleaned carboy ended up with me needing to add 10 oz of extra wine I had for that batch in order to top off container (B). I had less than 5 oz of sediment loaded wine leftover from that carboy so I estimating about a 4-5 oz difference in capacity. ( I only had 3 oz for our sample from that batch and poured out another 2 oz of heavy sediment)

3) Peach batch (Container D) was racked into the new emptied, cleaned, sanitized carboy from batch two(Container C). At the end of that racking I had to add 14 oz of extra wine set aside for that batch. ( I actually left 2 oz in the 16 oz bottle the extra wine was kept in. (Yes, it was under airlock) the leftover amount of wine with heavy sediment was 4 oz, alas there was nothing to keep for a sampling tonight.

_You are welcome to check my math and throw questions my way as I did enjoy those sample and my judgement now as I type this may be faulty. _


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## BernardSmith (Dec 7, 2019)

But liquid volume is not constant. It will change by temperature. So when you state that something holds 3 gallons at what temperature is that volume accurate? And does all liquid expand and contract at the same rate when heated or cooled?


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## sour_grapes (Dec 7, 2019)

BernardSmith said:


> But liquid volume is not constant. It will change by temperature. So when you state that something holds 3 gallons at what temperature is that volume accurate? And does all liquid expand and contract at the same rate when heated or cooled?



A temperature swing of 10 degF will change the volume of 3 gallons of water by about 12 mLiters, or about a tablespoon.


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## Scooter68 (Dec 7, 2019)

BernardSmith said:


> But liquid volume is not constant. It will change by temperature. So when you state that something holds 3 gallons at what temperature is that volume accurate? And does all liquid expand and contract at the same rate when heated or cooled?


 When you rack a wine from one container to another it doesn't change it's temperature significantly and as Sour_Grapes states even if it miraculously changed 10 degrees that would account for perhaps 1 tablespoon, not 10 ounces (or 20 times one tablespoon).

What we are talking about is when you rack a batch of wine from one carboy to another - folks are having situations where they find they are 1) Leaving 2-10 ounces behind and yet filling the new carboy. OR 2) Racking and leaving perhaps 4-6 ounces of wine (with sediment) behind and then needing to add 12 ounces or more of volume to top off a carboy. (My post above was with 3 gallon carboys.)


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## jvbutter (Dec 8, 2019)

jburtner said:


> I’m making much better effort now to keep it all topped up with absolute minimal headspace even though I also use headspace eliminators on the carboys.


Big reason I'm not liking the new Big Mouth Blubbers for aging... too much head space in the big necks. had a couple batches get nasty bacteria on top. Hopping to save them with good 4x meta solution



NorCal said:


> I've racked from one 5 gallon carboy to another and had it overflow by a significant amount. They vary within an few % manufacturer to manufacturer.


I think it alos has to do with wall thickness of the glass



BernardSmith said:


> But liquid volume is not constant. It will change by temperature. So when you state that something holds 3 gallons at what temperature is that volume accurate? And does all liquid expand and contract at the same rate when heated or cooled?


No joke, I use to top mine right up to the bottom of the cork, or within a 1" of it. Not anymore. With heat they expand and will rise up into your airlock.


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## Scooter68 (Dec 8, 2019)

So if my previous post left you slightly confused.... perhaps this will finish the job..


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## Ajmassa (Dec 8, 2019)

Scooter68 said:


> So if my previous post left you slightly confused.... perhaps this will finish the job..



Reminds me of an SAT math question! Lol. 

Carboy B is the largest 
Carboys A&C about -6oz. 
Carboy D is the runt at -10oz 
Final answer!

I’ve got a 5gal that’s more than 5.3gal actual.
A 6.5 closer to 7
And I have x4 54L demi’s which vary but the real drag is one of em has a larger bunghole than the others requiring a different sized stopper. It is what it is tho. Fughetaboutit. 

My LHBS supplier has their own direct glassmaker source. Take the good with the bad. Dirt cheap. But sizes tend to vary.


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## Scooter68 (Dec 8, 2019)

I agree AJMASSA - Makes my brain hurt figuring it out. 
And now that runt Carboy 'D' is the next one I have to rack into in a few days. Going to be interesting as the remaining 3 gallon batches cycling through the racking process should have virtually no sediment other than a dusting on the bottom. Time to get my smaller 12, 16, and 20 oz containers cleaned and ready for use. 
Before I rack again I'm going to do a real measurement of that carboy and I think I do have another spare that I should check as well. 

Yeah the bung fits are a real headache too. I keep splitting the small plastic ones that are supposed to fit my screw-top 1 gallon / 4 liter carboys. Need to find smaller bungs for those. So far the ones I've tried are too large and pop back out.


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## Mario Dinis (Dec 10, 2019)

whackfol said:


> Anyone know with some degree of accuracy what the volume of a "3 gallon" carboy is to the bottom of the spout? I'm fine with liters or gallons.
> 
> Alternatively, do you know the liter volume printed on the bottom of the "3 gallon" carboy and what height they are measured to on the carboy?
> 
> I have most of my different carboys graduated with volume markings but can't seem to find a 3G with markings.


I have three 6 gallon carboys and all three are different. What I did was put white electrical tape on the side of each of them and fill them a gallon at a time and mark the tape at each gallon poured. some people do etch the glass with markings.


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## Scooter68 (Jan 24, 2020)

*Three gallons vs 3 gallons +18.75oz !!!*
So it was a slow day for me, too nasty to do anything out side really - obviously a GOOD time to rack some wines on their 3 month cycle
AND I remembered to take the time to measure the volumes of each of 3 x 3gallon carboys. I filled each one to the same point - bottom of the fat ring on the neck. (See Image)I used an 8 cup plastic measuring bowl and of course it should have taken exactly 6 to get each one close to the top I would count the first as spot on for our wine making uses and the second acceptable but geet a look at number 3 !! [Oh Yeah I marked each on on the bottom for future reference and in this case Warning.]
1) Volume = 3 gallons .75 oz
2) Volume = 3 gallons 3 .75 oz
3) Volume = 3 gallons 18 .75 oz (Double checked that too)

The last one had squiggly lines on the bottom of it unlike the other two. Obviously 3 oz is no big deal but I was blown away by that third carboy volume.
Interestingly I checked and that equals a 402.750 ounces
11 liters = 387.145 oz
12 liters = 422.340 oz

Sort of at a loss on the best solution. Three gallons in the third carboy is well below the neck and has a surface about 7 - 8 inches across (Diameter) giving too much head space for aging.

I've got a total of 7 3 gallon carboys so I will have to measure and as I go through these I'll get them all checked out. 3-4 oz variance isn't a big deal. 7 ounces starts to create issues but this is crazy.

*On the upside when I racked from that third carboy today I had enough clear, sediment free Black Currant wine that we will have two glasses of wine tonight. It's about 9 months old so this is a good point to sample.*


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## Mario Dinis (Jan 24, 2020)

@Christopher Barbero, check out this thread about the question you asked me.


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## Scooter68 (Jan 24, 2020)

?? What Thread ??


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## BernardSmith (Jan 25, 2020)

Not sure I see the problem. Carboys are for use after active fermentation has ended. Buckets are best for use when you are pitching the yeast. The idea then is not simply to aim for a specific volume (given the loss to lees etc when you rack) but to aim for a specific SG at a larger volume than will fill the carboy. Of course, if you are working with kits that may be an issue... but 6 gallons at bottling should (I would argue) always be 6 gallons PLUS at pitching, ditto 5 gallons, ditto 3 gallons and 1 gallon. The exact volume of your glass carboys is then not really an issue, is it, if you design your must to exceed the volume of the secondary?


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## Scooter68 (Jan 25, 2020)

The problem comes into play when racking from one carboy to another. If my current carboy is right at 3 gallons +/- a ounce and the one I'm racking it into is 3 gallons 18 ounces, that's a lot of volume to make up. 
I rack every 3 months and unless I rack into one carboy, clean out the old and then rack back into that freshly cleaned "old" carboy their can be issues and it work both ways if the new carboy I rack into is a 3 gallon and the 'old' carboy is 3 gallons 18 ounces I'm going to to find another small container to put that excess wine into and airlock it.

Often I have 6 of my 7 Three gallon carboys filled with wine I'm aging. When it' time to rack them all I rack into the one unused carboy, clean-out the now empty one and tack the next carboy of wine into the freshly cleaned carboy and repeat that process until all the wine has been racked and dosed again with k-Meta. When the sizes vary so much it make it very difficult to keep track of the volumes of each carboy. If only one carboy is extra large I could rack into it, clean the now empty carboy and then rack again back into it but that's extra work and extra exposure of the wine to potential oxidation.


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## franc1969 (Jan 26, 2020)

I have 3 glass six gallon carboys, they differ just as wildly as you have found for your threes. I am now collecting PET carboys, as the glass is too dangerous to deal with. Also consistent in size, but still much more than the labeled volume.
Almost half a gallon more fits in my five and six gallon better bottles.


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## bstnh1 (Jan 26, 2020)

franc1969 said:


> I have 3 glass six gallon carboys, they differ just as wildly as you have found for your threes. I am now collecting PET carboys, as the glass is too dangerous to deal with. Also consistent in size, but still much more than the labeled volume.
> Almost half a gallon more fits in my five and six gallon better bottles.


I

Yep! I have several Better Bottle 6 gal. carboys as well as a couple of Vintage Shop carboys. Every one of them holds a different volume. The problem comes up when you rack from a "low volume" carboy into one with a significantly higher volume. You wind up with the wine level well below the neck of the carboy and way too much exposure to air.


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## Mario Dinis (Feb 2, 2020)

Scooter68 said:


> ?? What Thread ??


This one here about the carboy sizes.


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