Stopping the pump on a stuck mash

I was looking at the Adafruit Liquid Flow Meter, and thought about using it for stopping the mash pump and buzzing and alarm, in case of a stuck mash.

I would prefer stainless and something which is rated at more than 80 degrees Celsius, but it could be a place to start.

Does anyone have experience measuring flow during mash, from Arduino, Spark or a similar platform?

That’s very cheap for a flow meter. The ones used with kegbot are 50 usd (but have the same problem as described below) and brand Swiss Flow, if I remember correctly.

These things usually work with a propeller and pulse/revolution counting. I think they will get blocked when pumping cloudy wort from the mash.

I have searched for different flow meters that could be used on the hotside of the brewhouse and have not been able to find anything that is within reach for a homebrewer. Most of the products that fit into what we need (stainless, high temp, something that will not clog) are just out of reach unless you have tons of disposable income.

On the cold side of things you can find relatively cheap solutions for measuring volumes. I use this guy to help me dial in my input volumes:

If you do find something that doesn’t cost and arm and leg please do share.


What I would like to try out is pressure sensors to measure the weight of the water column.
If you have 2 at a know distance, you could:

  • Measure the SG (by measuring the weight of a known volume)
  • Correct volume for the SG

With the brewtroller implementation of pressure based volume measurement, they used freescale pressure transducers and measured the pressure in a stainless tube going down the beer. Downside of this is that you have to pump air into the tube continuously to prevent it filling up with beer. You are basically measuring the pressure at which the air escapes, which is the pressure at the end of the tube. By doing it like this, the pressure transducer does not have to withstand high temperature or liquids.

However, it would be simpler if we could find an affordable pressure transducer with a stainless membrane or something that can be in direct contact with the beer.

@Elco were they doing that all on the brewhouse side or fermentation side?


Brewhouse, you don’t want to pump air into your fermentor…

It would be a lot easier to design some type of floating door on the outlet side of your recirc. so when liquid is flowing the door will swing open and if it get s stuck or slow it’ll swing down. Similar to a door switch.

I think most people are using a grant for this situation. It’s just a secondary small vessel below the MLT that turns the pump on when low, and shuts off when high. You only need 4 fairly cheap and easy to install components 2 float switches, a relay, and a solenoid valve will automate a fly sparge and a vorlauf and eliminate problems like “air locks” that people have w/ the March pump.

For example (this one is complex with the wireless, but the concept is good)

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I have all the hardware to build the brewtroller solution, since I’d like to evaluate that. It’s been sitting in my basement for over 3 years so long overdue - the main issue is getting s/w support in brewpi. I’m particularly interested in measuring the flow in the HLT and into the BK as well as measuring SG in the BK during mash runoff and during the boil.