Double-barreled counterpressure bottle filler

This morning I tried out a new gizmo that I’ve been thinking about since last fall – a two-station counterpressure bottling rig.  I’m pleased to report that it works really nicely, and if I get a chance I’ll post pictures and maybe plans.

First of all, a counterpressure bottling setup is a piece of specialized plumbing that allows bottling of home-brewed carbonated beverages without losing most of the gas.  If you just use a tube with a valve on the end to dispense pressurized cider from a keg, most of the gas comes out as it passes through the valve, so the beverage comes out really foamy, you have to fill really slowly, and the end result turns out almost flat.

The solution is a counterpressure filler.  The basic concept is to fill the bottle with CO2 before introducing beverage, and then vent the gas from the headspace of the bottle slowly so as to keep most of the gas in solution.  Holly built one a few years back using swagelok fittings and a two-way valve from McMaster-Carr, and we’ve done all our bottling with it, but it has significant limitations.  You have to manually force it downward on the top of the bottle and sit there applying constant pressure while it fills.  If you get distracted and let it pop out of the mouth of the bottle, you get a minor cider volcano and a mess all over the table.  And, you can’t do anything else for the minute or so that it takes each bottle to fill.

So, this year I made two counterpressure filler units, mounted them on wooden arms that slide up and down and clamp onto two pieces of 3/4″ copper pipe arranged vertically about a foot apart and attached to a baseplate, and plumbed them in parallel to a keg of cider and a small CO2 cylinder.  In operation, one of the units is slid down in place over a bottle until its rubber stopper seats in the mouth of the bottle, and a handle is tightened to lock the unit firmly in place.  then the valve is turned one way to charge the bottle with gas, then the other way to start the flow of cider.  A needle valve controls the rate at which gas escapes from the top of the bottle between the central tube and the stopper, which in turn controls the filling rate.  While the bottle is filling, the operator is free to rinse and sanitize empties, cap full bottles, or prepare the next keg for dispensing.

Even in crude prototype form the double-barreled counterpressure bottling rig was a dramatic improvement over previous manual filler.  The wood-on-copper linear bearings leave a bit to be desired, but they did the job, and I was able to bottle two and a half cases in very short order before I ran out of gas, shortly after the welding shop closed for the weekend.  If I neaten up the plumbing and make a nicer base plate and slider arms, I think I will end up with a truly elegant system.


One Response to “Double-barreled counterpressure bottle filler”

  1. Rod Olsen Says:

    I am looking for an affordable CP filler for my small microbrewery in Queensland. How did yours end up and any chance of seeing some pics?
    Regards Rod

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