I think it would be useful to utilize a flow meter on brew day... has anyone tried this? Particularly I'm interested in measuring the volume going from my Mash Tun to the keggle and from the keggle to the fermenter. I currently use a steelhead pump to transfer from the Mash, but rely on marks notched into my mash paddle to measure volume. For this instance I would think it would be best to have the flow meter on the input side of the pump? After the boil, I whirlpool and then run the wort through a chiller to the fermenter. Would you hook a flow meter to the output side of the chiller, or still on the pump side? (My thought is on the output of the chiller you don't have a stream that fills the tubing, so it may give inaccurate results?). I appreciate your thoughts and would love pictures if you have them, surely someone else out there is doing this.
Maybe some larger brewhouses are doing so, but I think you'd be hardpressed to find a homebrewer doing so. It's not a bad idea, but all the flow meters I use daily, I certainly couldn't imagine using them for brewing. Calibrating them would be one issue, the other would be cleaning them. If you want a better idea of you losses, you could break it down easy one day and keep note. It's easy to find the average grain absorption. You check your volume there after the first run. Then again when you sparge and collect the 2nd runnings. What goes in is measured, and what comes out is easy to measure. The losses from kettle to fermenter will vary for length of boil, losses from hops, false bottoms, manifolds, pumps, tubes, etc. Eventually if you are consistent enough in your process, you will know what to expect % wise you'll have in your brewhouse from grain to even bottle. With that.. I'd think a flow meter would be overkill and wouldn't tell much in the long run, other than having something fancy to watch tick away for a minute or two while pumping into fermenter. For what it's worth, you'd want the flow meter on the output side, but it would work however you'd like it. It just measures what has passed by/thru it. Inconsistent flow, temps and weight can throw flow meters off, to the point it's not worth messing with them, so you'd have to judge where in your system would work.
short answer, not practical. a flow meter with the resolution a home brewer needs is expensive. an inline digital meter is easily over $200, but those will measure in 1 gallon increments and are not suited above 130 degrees or so. those meters are very common in water works and environmental projects. https://www.grainger.com/product/GPI-Flowmeter-1YEF8?s_pp=false to get the required 1 gpm flow rate we would need, expect to pay over $600. to get that meter capable of withstanding boiling temps, over $1,000. stainless steel and all. a more practical solution would be a brass construction "nutating disc" mechanical flow meter. but that wont get you near the flow rate required either, and because water main readers only need to provide a number within a few gallons, you're going to be guessing. and that will cost over $300. Cheers.
