Agitator RPM

What is the recommended RPM for an agitator.

I am looking at RPM for both mashing as well as heat up for a distilling run.


  • this isn't really answering your question but keep in mind a simple grist hydrator home made or store bought can save you alot of agitator power in the mash tun , because you dont have to deal with doh balls to break up . and you have added bonus of no dust in your mash room .


  • Thanks. BUT the agitator is a requirement in keeping everything in suspension whilst heating / cooking otherwise I am likely to get element scorching. Also to use whilst heating up so that even and faster heating is realised.

  • edited December 2017

    Read all these blog entries, good stuff.

    Mixer Direct Blog | mixer basics

  • Kothe use 150rpm if that helps.

  • What are StillDragon's agitator / mixers running at ??

  • edited December 2017

    10-20x gear reducers are pretty common for tank mixers. Large impellers (24”+) in wide tanks generally have the bigger reductions otherwise things get wicked fast. Long shafts at higher speeds need bracing.

    On our 600g mash tun we use a 20x reduction with a 30” impeller, 7/8” shaft, no bracing.

    Our 550g fermenters use 25x reduction on 24” impellers, same 7/8” shaft. We went very slow as the shafts are 4’ no bracing.

  • Thanks @grim. Various gearbox reductions are easy to get in conjunction with a 4 pole 1,400 RPM motor. But it's that magic number of recommended impellar rotation that I am after.

    Looking at what you have mentioned above;
    Tank mixers - 70-140 RPM
    600g - 70 RPM
    550g - 56 RPM

    @TheMechwarrior indicated 150 RPM for Kothe

    I found some other guys mentioning 40 RPM

    Surely there must be a guideline for what is recommended.

    Using a VSD on a 50Hz basis, you generally do not go below 20Hz for the lowest speed. So my thoughts based on this would be for a full speed of approx 75 RPM and a slow speed of 30 RPM.

    Thoughts on this, because you really do not want to stir the crap out of the still with massive vortices ??

  • 30 -40 rpm

    StillDragon North America - Your StillDragon® Distributor for North America

  • went and took look at the specs on our agitators one is 37 rpm in 425 gallon mash tun the other is 200 rpm in 200 gallon mixing tank . the 37 rpm is nice speed in the mash tun the one in the mixing tank is like a boat motor lol tim

  • @Smaug said: 30 -40 rpm

    so if we have plans to use a 2hp vfd on a SD agitator, is there any reason to change the stock gearing? thinking 'no', but being safe!

  • VFD for speed control? Or just a basic on/off function? Low RPMs on your set up is never going to whip up any froth. I'd go with a basic 20 amp toggle.

    StillDragon North America - Your StillDragon® Distributor for North America

  • We run the stock agitator at 50hz, does the job and is much quieter.

  • edited December 2017

    Use of different speeds ... The idea comes about because of use of it for;

    1. Cooking and Mashing
    2. Improved heat up time for start of distilling
    3. Ageing improvements with fast, slower and even slower agitation for Brandy, Gin / Vodka and Whiskey / Rum
  • edited December 2017

    It's 3 totally different mixers.

    1. Requires the most power, especially if you are dealing with stiff mashes. Consider that in this case, the agitator is mixing heavy grain sitting on the bottom of the tank. Large impeller, slow speed, high torque. It takes a serious agitator to keep grain in suspension at startup. High speed sheer mixers don't work, they make lots of motion in a small area, and can't keep grain in suspension.
    2. Requires less power than # 1. Fermented mash is significantly less viscous, and the grain solid volume is significantly reduced, remaining germ and skin/pericarp tends to be easily suspended. Unless you are dealing with true grappa, this agitator has a much easier job than # 1. You could use the same kind of agitator as in # 1, but it's seriously overkill here.
    3. Not sure what you are going for here. A small mixer is helpful for your final blend tank to be sure that your final mix proofs are dead on. However you are talking relatively tiny compared to the other two. In this case, even a small impeller direct drive is plenty. Keep in mind though. Some oxygen good, lots of oxygen bad - this would especially be the case with gin.
  • 100% @grim

    StillDragon North America - Your StillDragon® Distributor for North America

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