I would like to use the arduino to monitor and create the best beer. I've look up some info and the best way to look for quality is to measure the beer density. I could not find any digital Hydrometer that I could plug to my arduino. Are there any other ways to monitor the brewing process?

  • 4
    Just so you know, The arduino or any fermentation monitor is only one piece of the puzzle. You can brew great beer without these things, and having them doesn't necessarily mean you will brew great beer - you also have to have a certain amount of knowledge about brewing and the process. It's not clear from the question if you are an experienced brewer or not, but if not, then starting with some introductory brewing books would be a wise start, such as howtobrew.com
    – mdma
    Aug 9, 2012 at 19:34
  • Are you looking to track fermentation specifically? Arduino can do many other things with t-stat/relay type applications for controlling/monitoring mash temp, ferment temp. I think there is even a ph monitoring application. Not sure there is an easy way to monitor gravity/fermentation though.
    – DHough
    Aug 9, 2012 at 19:36
  • I've never done this, I guess you where right, I need to start first. I wanted to monitor the fermentation process because its the longest one.
    – EEstud
    Aug 9, 2012 at 19:38
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    "the best way to look for quality is to measure the beer density"....no. The best way to look for beer quality is to taste it!
    – Denny Conn
    Aug 14, 2012 at 15:55
  • There is a brewery controller out there called Brewtroller that is a custom arduino board. It's open source hardware and software. They have a version to automate your brew process and a version to automate fermentors (like a fermenting fridge). www.brewtroller.com
    – sgwill
    Aug 14, 2012 at 17:53

4 Answers 4


I am planning to use my arduino to control my brewing process. Eventually also to log fermentation temperatures. I didn't realize an electric hydrometer was possible. I plan to look into it.

Right now I am only controlling my mash heating for my HERMS. Eventually I will be able to monitor temperatures with multiple probes simultaneously, Adding data logging, and other features. I will share more details once I get all the kinks worked out.

In my opinion you absolutely do not need any kind of electronic controls to make good beer. Sanitation, happy yeast, and the brewing process are what make good beer. I just happen to enjoy tinkering with electronics, and one day they may allow me to be lazier on brew days.


I've not seen any inexpensive density sensors either, which is surprising since they can be made from mass-produced components - a PZT actuator and a quartz tuning fork. The sensor works by producing a vibration and then measuring the resonance in the tuning fork to that vibration. The density of the liquid has a predictable affect on the resonant frequency, i.e. the point with the highest resonance, and so from measuring the resonant frequency the density of the liquid can be determined.

The paper here describes how to build such a sensor, and how it peforms. If you search for the title, you can also find the full text.

  • 1
    I would add that you could just weigh the fermentor before and while the wort is in it. Since you know the volume, the weight will give you the density. As fermentation proceeds, the weight will drop (as C02 is released)
    – daveb
    Aug 30, 2012 at 15:17
  • What about drift? most reasonably priced sensors have quite significant drift. I've seen project using load cells to determine the amount of beer left in a keg report this as a significant loss of accuracy.
    – mdma
    Aug 30, 2012 at 15:31

Uses Raspberry Pi and Arduino to hack a fridge. Active support community.


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    Yes, good fermentation control definitely improves the quality of the beer - control with low fermentation rate in the beginning to limit off flavors and then increase temperature towards the end to improve attenuation.
    – mdma
    Dec 12, 2013 at 22:01

Make mag has some great stuff and this seems promising: https://makezine.com/2014/03/28/homebrewing-and-arduino-the-perfect-recipe/ Includes links to open source projects. I know I'g going to check it out.

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