I'm looking for an auto shut off for keg filling. Not the little ball and site glass thing from GW Kent, and not a $20k fully automated machine for commercial breweries. Just a simple electrical actuated valve that gets its signal from either a scale or a flow meter. None of my Google skills have resulted in finding anything. But based on the cost of the various components (budget class valve, PLC, scale or flowmeter), this should be available for well under $500.

Anyone aware of anything like this before I make it myself?

  • Measuring the volume loss from the bright tank / fermentor isn't an option? Aug 18 '18 at 0:39
  • @EvilZymurgist anything is an option if it can be made automatic. What exactly did you have in mind? There's a site glass on the brite tank but obviously that can't be used in any automatic way. Even if it was, there is a big latency between when the volume inside the tank changes and when the site glass reflects the change. It also starts at 10 gallons. So to use it when filling 5 gallon kegs means that the last two would be totally blind. Aug 20 '18 at 14:27
  • Also, regarding the site glass, the scale is printed on the side of the tank in increments of about 0.5" = 5 gallons, and the site glass tube itself is a good 1.5" away from that. So you have to kneel down and position your line of sight to be exactly horizontal or your reading will easily be off a gallon or two either way. Aug 20 '18 at 14:32
  • So far, every commercial keg filling machine I've found from searching uses a flowmeter inline. That's probably the ticket. And I haven't found anything for the < micro market. The machines I've found start at $10k. Seems like an opportunity for an SS Brewtech-like vendor. Or maybe there's no demand for it in the home and nano markets. I just know it drives me nuts not being able to manage what's going on. Aug 20 '18 at 14:34

Commercial fillers with auto shut off work on one of two principals. Over flow or gravity.

Over flow systems use an overflow tank that also connects to the main source tank. This tank then uses a float sensor for the shut off. The overflow is then used in the next fill. These are very expensive and are a whole new system that requires sanitation.

Gravity fillers use a prefill tank either using a float shut off or a load cell to measure the weight. The load cell versions are not that practical for brewing because different beers have different liquid gravity and can leave a keg short or over filled. The float versions are more practical for brewing and cheaper.

I don't think you will find any reliable plug and forget system for anywhere near $500.

Most breweries short of an automated kegging line have manned filling stations and simply rely on a clear exit line for manual shut off.

  • Interesting. I'm still not clear as to why you can't just a) measure the flow of product through a tube or b) measure the weight change of the keg? Those are two very simple design approaches. Aug 20 '18 at 15:03
  • But if no one does that, I am assuming there's something wrong with those approaches. Both would be under $500. I am receiving a $250 low profile platform scale today with a remote display. I'm going to start with that and see if or why I can't just zero it out with an empty keg and then slow the flow and ultimately close the valve as it approaches and hits 5 x 8.33 pounds. I've filled enough kegs on this setup that I know the slowing and stopping part is totally doable. The only thing I'm missing is the accuracy as to when to do that. So I need feedback data on either flow or weight. Aug 20 '18 at 15:04
  • In any case, I'll mark your question as the answer because the question was is anything available on the market and it appears there's not. Thanks! Aug 20 '18 at 15:06
  • @MarkBostleman using a weight/gravity system has the fault of not every beer has the same weight to volume so kegs will be underfilled if you use say water as the control weight. While this is negligible it may have issues from beverage control agencies if your advertised volume is specific. Aug 20 '18 at 16:50
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    Kegs vary in weight too. From a process control standpoint, the product weight would have to be considered in the same way as the tare weight is set but on the opposite end (the ending weight, not the starting weight). So instead of going to 42.25 lbs as you would with water, you offset up or down to based on the product. I don't see that as being a show stopper. Aug 20 '18 at 17:07

NB - this is not an autoshutoff as such, but may help with your needs.

You could daisy chain all your kegs so that when keg 1 fills up, it automatically starts filling keg 2 and so on. I have a pressurisable fermenter, and I've been doing closed loop transfers, which have worked really well for me. You can transfer carbonated beer nicely with this method too.

Make sure the fermenter is elevated compared to the kegs.

Once all kegs are sanitised and purged, connect gas port on fermenter to gas port on the last keg to be filled, then liquid-gas, liquid-gas up the line until you reach the first keg. This equalises the pressure in all the kegs with the fermenter. Disconnect the gas connection to the fermenter, and hook up the liquid out of the fermenter to the liquid in of keg 1. Nothing should happen. Slowly vent some gas from the final keg. Once the liquid has started flowing, reconnect the gas ports on the final keg and the fermenter. A siphon has been established, and you can walk away and come back later. 1 of two things will happen - all the beer will fit in the kegs and you'll have no overflow, or not all of the beer will fit in the kegs, and beer will fill the gas out hose from the final keg to the level remaining in the keg.

  • Addition: I have found that having each keg a little higher than the next makes this much more reliable. So keg 1 is lower than the fermenter, but higher than keg 2, and so on.
    – Frazbro
    May 10 '19 at 2:13

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