filling a mini keg from a 5gal corny, critique my plan

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odie

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I'm going camping this weekend and I'm going to fill some 1.6 gal mini kegs to toss in an ice chest. I usually just fill growlers from the tap but this time I want to have a draft set up for camping.

I have some freshly fermented kegs that I want to transfer beer into the mini kegs to take with me. These kegs were fermented in so they are completely sealed from any oxidation and mostly fully carbed. They are around 20-30 psi at room temps while waiting for an open spot in the kegerator.

My plan is this.

1. fill mini keg with water and weigh it to determine full/target weight. then empty it.

2. place empty & sealed mini keg on scale next to full keg.

3. connect mini keg to full keg with beer. "out-to-out" or "beer-to-beer" post jumper.

4. pressurized full keg will push beer into empty keg until pressure in both kegs is equal.

5. vent mini keg and/or add CO2 to big keg as needed to maintain beer flow.

6. vent mini keg PRV until mini keg scale reads full/target weight on mini keg.

7. remove jumper.

8. CO2 purge mini keg headspace a few times to remove residual air.

9. Pressurize mini keg with carb chart and chill.

I have a separate mini CO2 source for travel.
 
If it helps; I have 3 of those 1.6 Gallon chinese mini-kegs and the bottom of the gas diptube is exactly at 6 litres, meaning any more going in the liquid tube while sealed, is pushed through my bowtie spunding valve on the gas post when I fill mine..(not ideal I know, but hey, it cleans easy). If your scale does metric, 1 litre of water is 1 kg, beer is just a bit heavier depending on the gravity, but forgot the simple math to calculate it.
 
Perhaps trim the gas tube? It only needs to be deep enough to hold the o-ring.
 
You didn't mention CO2 purging the receiving keg before filling.

I also like @Broken Crow 's method of using a spunding valve on the receiving keg to automatically control the pressure in the receiving keg to slightly less than the pressure in the source keg. Pre-pressurizing the receiving keg should also minimize foaming in the receiving keg.

Brew on :mug:
 
I think pre-pressurize the mini keg with CO2 is good so that you don't get an initial blast of beer and foam.

Spunding valve would give control over the flow rate.

It will purge as it spunds. Some CO2 is going to break out of the beer as it fills the keg. Head pressure will help control some of that.

The CO2 purge will happen at the end when headspace is minimal.
 
After you fill the mini to get weight, instead of just dumping the water, use CO₂ to push it out and you will be starting with a purged keg. I don’t have a spunding valve, so I would just do a slow gravity transfer at this point. As soon as I get the wine out of my 2 gallon keg, I’m going to give it a try.
 
After you fill the mini to get weight, instead of just dumping the water, use CO₂ to push it out and you will be starting with a purged keg. I don’t have a spunding valve, so I would just do a slow gravity transfer at this point. As soon as I get the wine out of my 2 gallon keg, I’m going to give it a try.
I thought about that. I'll probably be having to fill it with CO2 anyway to get both keg pressures equalized so I don't have a blast of foam.

My only concern is there would be some residual water in the keg. But I guess, even if I rinsed and drained the keg, there would still be residual water anyway.

To truly purge the keg, it would have to be full of water to the brim when I closed it, then CO2 to push it out.
 
well, the weight test was "interesting".

pretty much came out to almost exactly 4 pound increase for each 1/2 gal increment as I filled. water is 8.34/gal.

obviously a little container error on my part. Not scale error (digital).

beer being lighter than water I will have to "estimate" when nearing full.

Or just let it fill until beer comes out the gas post or PRV? When I tap it, it will drop anyway.
 
The reason I mentioned the measurements is that I've made some assumptions; That you've got the same mini-kegs as me, and that your full kegs are regular 5-gallon cornys. I've taken a break from brewing my own at this time while I rebuild my entire brew-rig to make it more compatible with my disability (Which, apart from spine and CNS, includes brain damage which is why my posts sometimes meander and are full of typos and wrong or missing words). The injury was on the job, which in Canada means I've been left slightly above the poverty-line for the rest of my life but I like 'good' beer that I can't afford to buy, but I can make better for half the cost so.... My LHBS has a 'we brew it' service and their beers are almost as good as mine and still cost only about half what it would cost for a commercial brew, but they can only do closed transfers to sankeys...their very expensive high-end sankey filler craps out from the back-pressure of the smaller corny post, so I buy sankeys from them, in 25 litre batches, which requires 1- 5G corny, and one mini-keg. I've relied on that 6 litre gas-post level and fed the mini-keg from the sankey, with the gas post chained to the liquid post on a five gallon corny (approx 19 litres).... I know daisy-chaining is not always a good idea because it increases foaming, and I've had mixed results doing this way, but if I just do it slower..it works.
I don't know how many mini-kegs you have, but if you didn't mind going really slow, you could daisy-chain 3 of them and get 18-litres (6 at the gas post of each one) out of one full sized 5G ('19litre') corny, and if you tilt the mini-kegs, gas side up an inch or so while filling, you could probably get an entire 5g corny into it.
Dunno if that's useful to you or not.
:mug:
 
beer being lighter than water I will have to "estimate" when nearing full.
Beer is heavier (more dense) than water, unless your FG is less than 1.000.

Water weighs 8.3304 lb/gal at 68°F, and 8.345 lb/gal at 39°F. The formula for volume from weight is:

Volume = Weight / (Water Density * FG), or​
Weight = Volume * Water Density * FG​
Brew on :mug:
 
Beer is heavier (more dense) than water, unless your FG is less than 1.000.

Water weighs 8.3304 lb/gal at 68°F, and 8.345 lb/gal at 39°F. The formula for volume from weight is:

Volume = Weight / (Water Density * FG), or​
Weight = Volume * Water Density * FG​
Brew on :mug:
oops...yeah, was thinking alcohol was lighter. forgot about residual gravity..lol
 
If it helps; I have 3 of those 1.6 Gallon chinese mini-kegs and the bottom of the gas diptube is exactly at 6 litres, meaning any more going in the liquid tube while sealed, is pushed through my bowtie spunding valve on the gas post when I fill mine..(not ideal I know, but hey, it cleans easy). If your scale does metric, 1 litre of water is 1 kg, beer is just a bit heavier depending on the gravity, but forgot the simple math to calculate it.
I too put a blowtie spunding valve on my gas post when filling any keg (fermenter to keg or big keg to little keg) but I put one of these in between the spunding valve and the gas post: Duotight Flow Stopper Automatic Keg Filler | MoreBeer It shuts off the flow of things on it's own.
 
one keg went flawlessly. One did not...please see "floating diptube issues" thread.

Slow and steady. The spunding valve kept it nice and even since the source kegs were around 30 psi before I burped them. Just a couple psi difference is all that was needed.

The rate of the source beer gassing off into the burped headspace was about the same rate at the spunding valve. So basically the source pressure held steady during the whole transfer. But it was all room temperature. If it was already cold the source PSI would have been about 10 and probably needed a CO2 boost to keep it moving.

At the end, I tilted the keg to keep the gas post clear of rising beer in order to max it out. 1.6 gal keg but I probably got a solid 1.75 or more in it.

20230301_200535.jpg
 
I'm going camping this weekend and I'm going to fill some 1.6 gal mini kegs to toss in an ice chest. I usually just fill growlers from the tap but this time I want to have a draft set up for camping.

I have some freshly fermented kegs that I want to transfer beer into the mini kegs to take with me. These kegs were fermented in so they are completely sealed from any oxidation and mostly fully carbed. They are around 20-30 psi at room temps while waiting for an open spot in the kegerator.

My plan is this.

1. fill mini keg with water and weigh it to determine full/target weight. then empty it.

2. place empty & sealed mini keg on scale next to full keg.

3. connect mini keg to full keg with beer. "out-to-out" or "beer-to-beer" post jumper.

4. pressurized full keg will push beer into empty keg until pressure in both kegs is equal.

5. vent mini keg and/or add CO2 to big keg as needed to maintain beer flow.

6. vent mini keg PRV until mini keg scale reads full/target weight on mini keg.

7. remove jumper.

8. CO2 purge mini keg headspace a few times to remove residual air.

9. Pressurize mini keg with carb chart and chill.

I have a separate mini CO2 source for travel.
I would make a small change to step 1, instead of water I would fill the barrel with sanitizer and then I would do an intermediate step between step 1 and step 2.-
I would dislodge the water from the barrel by injecting co2 so the barrel is sanitized, purged and presurized.-
Regarding the difference in density between water and beer, although it is true that beer is somewhat denser than water, it must be taken into account that, although little, there is also CO2 dissolved in beer, which decreases its density .-
 
I too put a blowtie spunding valve on my gas post when filling any keg (fermenter to keg or big keg to little keg) but I put one of these in between the spunding valve and the gas post: Duotight Flow Stopper Automatic Keg Filler | MoreBeer It shuts off the flow of things on it's own.
Thank You!! I've looked at those things before, but owing to brain damage, I am unable to understand fully how they work... do they really arrest flow when foaming rises? Would it worth my time and money to max out transfer rates to incorporate one in my transfer routine?
 
Thank You!! I've looked at those things before, but owing to brain damage, I am unable to understand fully how they work... do they really arrest flow when foaming rises? Would it worth my time and money to max out transfer rates to incorporate one in my transfer routine?
It can stop flow when foaming happens (i do my best to make sure no foam happens though and am usually pretty successful) but it works by that little white ball in the plastic sight glass. The trick is you have to keep the sightclass perpendicular to the floor because the way it works is as liquid comes out the gas post and starts to fill the plastic sight glass, the little white ball starts to float. As the liquid rises, the ball will reach the top hole before the liquid and as long as there is sufficient pressure from the incoming liquid, the ball will plug the whole and flow stops. It works well for me after the first couple tries, though I figured out the first couple tries that it needs to be as close to perpendicular as possible, but one I figured that out it's been smooth sailing.
 
mini keg fill version 2.0

filled another couple kegs last night for another camping trip.

this time, after filling the kegs to the brim with water (after complete cleaning and spraying with starsan), I then jumped gas to gas posts INSTEAD of using a CO2 bottle to purge the mini keg.

The supply keg was around 30 psi (room temp). I put a picnic tap on the receiving keg and opened it. Once I connected the gas-to-gas jumper, the mini keg ejected all the water in short order using the CO2 from the source keg. Last time I wasted CO2 from my tanks.

Then I removed gas jumper, installed spunding valve on receiving keg, and installed beer-to-beer jumper. Remaining PSI in the supply keg filled the mini in short order.

On one keg I wasn't paying attention and it went way faster than expected. Soon beer was coming out the spunding valve so I yanked it and cleaned it. But the keg weight checked very full. The gas tube is cut short so It's probably more than the 1.6 capacity.

All that is left is to check the final PSI in both the kegs and adjust as necessary for temperature using a carb chart.
 
I too put a blowtie spunding valve on my gas post when filling any keg (fermenter to keg or big keg to little keg) but I put one of these in between the spunding valve and the gas post: Duotight Flow Stopper Automatic Keg Filler | MoreBeer It shuts off the flow of things on it's own.
that flow stopper looks trick.

But I have no idea what the spring does or why it's even in there.

Kinda sucks they don't include the ball lock fitting because you can't use a standard one. They are at an angle so the stopper will not be upright. the 90 degree ball lock connector is required. or find a 45 degree doutight fitting.
 
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that flow stopper looks trick.

Kinda sucks they don't include the ball lock fitting because you can't use a standard one. They are at an angle so the stopper will not be upright. the 90 degree ball lock connector is required. or find a 45 degree doutight fitting.
I bought the flow stopper before the duotight ball lock fittings came out so I used some extra eva barrier tubing and cut a longer piece from ball lock to flow stopper so that it's flexible. I use a spring clamp to hold the flow stopper it straight up and down against something. I will one day splurge on the duotight ball lock fitting though cuz they're slick :)
 
I don’t get it. Your beer sounds like it’s gonna last 2 days tops. Unless it’s a hoppy ipa, spray the kegs down with starsan and fill them however :)

At least that’s what I do. Beer is gone before it oxidized.
 
The demonstration of the flow stopper suggests the keg is virtually full at the end. That's a problem for uncarbonated beer as once the keg is full enough to hit the very top of the sidewall, filling beyond that shrinks the surface area that will be exposed to CO2. Unless one's keg has a gas dip tube long enough to reach down to the same height just before the keg starts tapering at the top, it's going to take longer to carbonate the beer therein. And looking at the neck on the small cylinder used for the first part of the demonstration suggests it was likely filled near the very top...

Cheers!
 
The demonstration of the flow stopper suggests the keg is virtually full at the end. That's a problem for uncarbonated beer as once the keg is full enough to hit the very top of the sidewall, filling beyond that shrinks the surface area that will be exposed to CO2. Unless one's keg has a gas dip tube long enough to reach down to the same height just before the keg starts tapering at the top, it's going to take longer to carbonate the beer therein. And looking at the neck on the small cylinder used for the first part of the demonstration suggests it was likely filled near the very top...

Cheers!
Agreed, all my kegs have the gas dip tube though. One way around this if you don't have the gas dip tube is to hook gas up to the beverage out to whatever PSI you ultimately want the beer to be carbed at then slowly rock the keg back and forth. The gas will go into solution as it enters the keg and will stop going into solution once it's fully carbed. It's manual work but only takes usually 5ish minutes in my experience though I usually start pretty high with the PSI then slowly lower it down.
 
I don’t get it. Your beer sounds like it’s gonna last 2 days tops. Unless it’s a hoppy ipa, spray the kegs down with starsan and fill them however :)

At least that’s what I do. Beer is gone before it oxidized.
No it doesn't last long at all.

but it sometimes sits stored for several days before serving.
 
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