Ferment in keg ... how to measure volume?

[chordwizard]

I just received a 6.5 gal keg to use as a fermenter and had this duh moment ... how am I going to determine how much wort I actually transferred from the boil kettle? Visibility is limited so ... some sort of stick? weight?
Those of you that use kegs how do you determine your volume?

 

[balrog]

Weight.
But you have to have a scale that will stay on. Many of the cheaper battery ones will auto-turn-off after too little time.

 

[balrog]

Like this one
https://www.amazon.com/gp/product/B00KYA0RC2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

 

[day_trippr]

Weight. Pure water weighs 8.32 pounds per gallon, so add the empty keg weight to say 5 * 8.32 to calculate the expected full keg weight with a fairly small error (which will slightly reduce how much "beer" ends up in the keg - a good thing!)

And @balrog is correct, some scales will turn off to conserve battery power, so obtain a scale that doesn't shut off when on "wall wart" power. But if you avoid using NET weight and use GROSS weight instead you can lift the keg off the scale, turn it on and let it tare, then set the keg back on the scale...

Cheers!

 

[Yesfan]

Have to agree with the others. I have one of those scales that auto offs and it's a pita at times, plus it's got a small footprint.

Another thing to add. On my kegs, I added labels that have their empty and full weights on them. That way, I still have a reference if my scale shut off during mid fill.

 

[balrog]

Have to agree with the others. I have one of those scales that auto offs and it's a pita at times, plus it's got a small footprint.

Another thing to add. On my kegs, I added labels that have their empty and full weights on them. That way, I still have a reference if my scale shut off during mid fill.

2" blue painter's tape on all my kegs with tare (empty) weight.

I still re-weigh/re-tare prior to filling. Because, well, I can't not. Like an extra leftover 13 ml of StarSan makes a difference. Can't help myself.

 

[Drewch]

I'll second the utility of a good postage scale like the one linked above. I have one that goes up to 50kg that doesn't auto-off.

At room temp 1 L = 1000g of pure water. So a 1.050 OG -> 1050g/l wort. The math is stupid easy in metric.

 

[chordwizard]

Thanks for the replies folks!
I was afraid that would be the response ... another $50. to spend I guess

 

[mac_1103]

another $50. to spend I guess

OK cheapskate, just stand on your bathroom scale holding the keg until it's full.

 

[balrog]

Thanks for the replies folks!
I was afraid that would be the response ... another $50. to spend I guess

Hey, you can always fill until it starts shooting out the gas in post (assuming you are filling from the liquid out side).

I've done that.

You'd be wise to avoid it.

 

[Beekeeper]

One cheap route is to use a "fish scale." That is what I use. I weigh the keg, check the SG with the refractometer, determine how much distilled water I need to hit my target SG.

 

[Climb]

I measure the volume of chilled wort in the BK and then subtract the displacement volume of the IC and subtract the approximate volume of what gets left behind in the BK. After all the BK has volume markings; why not use them.

 

[whoaru99]

Hey, you can always fill until it starts shooting out the gas in post (assuming you are filling from the liquid out side).

I've done that.

You'd be wise to avoid it.

I was thinking that's actually not a bad way as long as you have a hose on the gas QD to direct a bit into a catch can.

Could even set the keg just slightly tilted away from the gas post side so when it starts venting the fluid will be slightly below the gas tube when the keg is straight up.

Is there something more to it I'm missing?

 

[balrog]

I was thinking that's actually not a bad way as long as you have a hose on the gas QD to direct a bit into a catch can.

Could even set the keg just slightly tilted to the gas post side so when it starts venting the fluid will be slightly below the gas tube when the keg is straight up.

Is there something more to it I'm missing?

It’s why many on here recommend removing the short dip tube on the gas in side and cutting it down so it doesn’t stick into the keg at all. It really only needs to be there to hold the o-ring in place for the seal.

 

[whoaru99]

For the extra volume?

In either case if using for fill indication it still would spew out when it gets to the hole.

 

[balrog]

For the extra volume?

In either case if using for fill indication it still would spew out when it gets to the hole.

Right. Extra volume. I have some kegs whose gas in tubes reach further than others, and they’ll take only 4.6-4.7 gallons before spewing. I really need to cut those. Soon. I promise.

 

[day_trippr]

There is some irony that the oem gas dip tube length was literally set so overflow out of it would indicate the keg was filled to the intended 5 gallon volume.

I cut all of mine down to 3/8-1/2" total length. Hence, filling by weight is the only reliable way left...

Cheers!

 

[yowzers]

I use this device, which is also very handy once you transfer to your serving keg of course. Minor modification, leave the large black magnet on the outside while you fill it. You can "feel" the level by sliding it up while you fill it. It's really quite easy once you try it. www.ballandkeg.com

 

[Yesfan]

Thanks for the replies folks!
I was afraid that would be the response ... another $50. to spend I guess

Check Northern Brewer. Sometimes they have specials and you may be able to score a pack of scales on the cheap. I got a "3pk" earlier this year that had the main one for grains, a mid size, and a pocket for salt additions.

Don't need all three or don't want to spend more? You may find the same style of scale much cheaper on Amazon then. I know my large scale is the same as what's offered by Anvil. I'm sure it's a Chinese brand made for both.

 

[oakbarn]

It does not need to be rocket science. Use the TLAR method. (That looks about right), You can add tape on the outside at the gallon marks and adjust visually. You will be close. BUT remember the Knudsen. Leave some headspace!

 

[balrog]

remember the Knudsen

Pardon my ignorance, but, Wha?
Google doesn't even help me:

 

[oakbarn]

Darn spell checker: Krausen

I likey put a "D' in it as we call it "krudsen" after crud!

 

[dmaxweb]

There is some irony that the oem gas dip tube length was literally set so overflow out of it would indicate the keg was filled to the intended 5 gallon volume.

I cut all of mine down to 3/8-1/2" total length. Hence, filling by weight is the only reliable way left...

Cheers!

Did you just use a hack saw?
Do any of the vendors have short one? I've only found 1-1/4".

 

[day_trippr]

Dremel with a virgin fiber cutoff wheel. I gouged out a pair of soft pine blocks to hold the flange end, chucked the assembly in a bench vise, cut off the tube end, then used the cone grinder to clean up the inside and outside edges...

I've never seen anything that short being sold, just the stock length gas tubes...

Cheers!

 

[mac_1103]

Do any of the vendors have short one? I've only found 1-1/4".

There is the UNI dip tube from Homebrewer Lab. 3/4" and doesn't need an o-ring. Probably not worth the $3 price plus $4 shipping unless you're buying a FLOTit 2.0 anyway and want to throw it in. Also available (for $6) from William's Brewing.

 

[day_trippr]

One way or another, beer or gas, a dip tube used on a cornelius keg needs an O-ring under its flange.
UNI dip tubes have an integrated "bonded" O-ring...

Cheers!

 

[mac_1103]

The UNI dip tube is made of silicone and stainless steel. In essence, it is its own o-ring. Hence the name.

 

[day_trippr]

Right.
Just didn't want to leave the magical impression that a dip tube could work without a compliant seal

Cheers!

 

[dmaxweb]

One way or another, beer or gas, a dip tube used on a cornelius keg needs an O-ring under its flange.
UNI dip tubes have an integrated "bonded" O-ring...

Cheers!

Speaking of o-rings. I've always used Buna-N round profile and replaced them every fill just to be safe. Like everything else, CO2 is getting too expensive to just let it drift away. On top of that, I've been working on a bag of them for quite a while and I need a fresh bag. Is there an advantage to the quad-x rings?

 

[day_trippr]

For the dip tube O-ring the quad seal style offers a greater surface contact than a conventional O-ring - which is probably why the OEM rings were quads. But for the other 'rings I don't think quad seals would offer an advantage...

Cheers!

 

[odie]

fill it with 5 gallons or whatever your target is. measure and mark the keg.

I ferment in 5 gal kegs. I fill a full 5 gal and it come to the weld line at the top where the side and top seam is. there is still 1/2 gal free space for krausen which I find to be plenty. just pop a blow off tube on the gas post.

 

[Yesfan]

fill it with 5 gallons or whatever your target is. measure and mark the keg.

I ferment in 5 gal kegs. I fill a full 5 gal and it come to the weld line at the top where the side and top seam is. there is still 1/2 gal free space for krausen which I find to be plenty. just pop a blow off tube on the gas post.

Living dangerously.....I like that.

Years back in my early brewing days, I remember coming home from work and hearing this slight hissing/whistling sound and wondering, "what the h-ll is that?!" I checked on my fermenter and saw where my S bubbler was caked with krausen. This was in my old Northern Brewer 6 gallon bucket (which I still have).

That's kept me paranoid when fermenting in kegs. I have just stuck with 4 gallon batches.

 

[Indian_villager]

Cheap ass luggage scale. Weigh the keg when empty, record the tare weight, fill your keg, figure out mass of beer you added, divide by density of beer which you can calculate from your SG as noted above.

https://www.amazon.com/Etekcity-Por...06109644&sprefix=luggage+scale,aps,117&sr=8-5

 

[Clint Yeastwood]

I hit my OG and then jam whatever I can in the keg. I try not to go too far, and I add Fermcap.

 

[dmaxweb]

Habitat for Humanity Restore $5.00

No batteries needed.