Soda Fountains, Soda Guns, and Remote Chillers

(This article is WIP and subject to change.)

So I’ve talked in the past about the Web Bar that I’ve built in our Family Room. It’s still a work in progress – in fact, it still needs at least $500 in plumbing done. It had occurred to me that if I ever wanted a soda fountain or bar gun to work, I needed to plan that part out in advance.

My Wet Bar

My Wet Bar

Without spending a whole lot of time explaining that which is already explained more eloquently elsewhere on the web, there are two kinds of soda fountains – pre-mix, and post-mix. Pre-mix is essentially the way my kegerator is set up already, only instead of having mead or cider in the kegs, you have “pre-mixed” soda in the kegs, with a regulator set to 100psi or greater – my regulators currently top at 30psi. These set ups are common at outdoor events – carnivals, high school football games, anywhere you see a soda keg sitting there.

Soda/Corny Keg

This is a soda keg.

Post-mix is far more common, and more readily recognized by the average person. It’s more complicated, but when done properly, it is more energy efficient. This is where the soda syrup is stored, typically at room temperature, with CO2 pumps that drive the syrup to the soda faucets. You then have a source of carbonated water, typically from a carbonator hooked to the water supply. The two lines are then sent through a flash chiller of some kind, bringing the temperature down beneath 40 degrees Fahrenheit, but not lower than 32 degrees, lest you make soda ice. :) This is typically accomplished using what is called a “cold plate”. Think of it as a radiator. You have a line for carbonated water, and a line for each of your flavored syrups. They zig-zag back and forth through this solid aluminum plate, which itself is submerged into an ice bath.

Cold Plate

This is a cold plate.

There’s a temptation to take a cold plate and stick it into a freezer. You can’t do that – the plate will drop below 32 degrees, and your lines will freeze up. You want something akin to dumping a bunch of ice in a cooler. That cooler may get down to 32, but that ice is going to begin melting. You have a wet “ice bank”.

Your alternative is to get a soda fountain that itself has a compressor that will create an ice bank for you – all you do is pour in water that will never come into contact with your beverage. The thermostat connected to this compressor is somehow smart enough to know how cold is “cold enough” to create an ice bank but not cold enough to freeze the lines. These fountains are super expensive. I found one locally used – a Lancer 8000 series, and they wanted $1200 for it. Cornelius makes their “Vantage” soda fountain, and the price is comparable.

So that leaves my idea set up to be a small postmix fountain, using a bar gun – since instead of a huge fountain, you just have a little gun with buttons, and a remote chiller like this:

The Soda Gun - Remote Chiller

The Soda Gun - Remote Chiller

The big black box is a “remote chiller”. Inside that box is the carbonator, the cold plate, and a small recirculating pump (more on that in a moment). The box is then filled with water. The water begins to form an ice bank on the coils, but doesn’t actually freeze the water solid. This chills the water and syrup in the lines, plus with this design the water stored in the carbonator is chilled to near-freezing. The recirculating pump then runs a single line of the chilled water up to the bar gun, but doesn’t connect. It instead does a u-turn and returns back down to the remote chiller. This is to keep the water and syrup that is in the line to the faucet cold.

That remote chiller isn’t cheap. I priced it out at the vendor, and he said that they “manufacture them, and they cost $1500″. OUCH.

So what’s the anatomy of a remote chiller? Looks a whole lot to me like a mini fridge turned on its side, compressor turned to match, with a thermostat that knows how to regulate the temperature just so. Mini fridges can be had for almost nothing on craigslist, in fact in April and May you can probably pick a few up for free with college getting out for the summer.

Then there’s the matter of the thermostat. The fastest of searches turns up the Ranco K14 Cooler Ice Bank Thermostat. $25 on eBay. Googling for “ice bank” thermostat will yield what you need.

Seems to me the order of operations here is:

1. Get a mini fridge.
2. Remove all electrical components (there’s not much there).
3. Turn sideways and fill with water. Verify that it is water-tight. If not, make it so. :)
4. Drain water, dry well. Rotate the compressor 90 degrees to the ground so that it is up and down, like this:

Mini Fridge to Chest Refrigerator Conversion


5. Replace the stock thermostat with your ice-bank thermostat.
6. Fill a bit more than halfway with water, plug it in.
7. Verify that it creates a functional ice bank.

Granted, I’m making several presumptions – but my own mini fridge only seems to get down to 38 degrees. We want near-freezing all the time, and that just won’t do it.

Jul04

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