I'm building myself a stir plate out of some things from my scrap heap of computer parts (mainly an old external hard drive and a case fan). I've used it in its prototype stage for one yeast starter already. It worked well enough, but it was a bit finicky, especially once the starter got thick with yeast.

Since the initial testing I did with a flask of water didn't accurately represent the stir plate's performance on a yeast starter, I want to test it on something thicker as I put the finishing touches on the build. I probably should've saved a jar of trub from my last batch, but it's too late for that now.

How can I make a couple liters of something with the consistency of a yeast starter for cheaper than actually buying a pack of yeast and making a starter?

  • Or another thought, buy a pack of yeast, make a starter and just fridge it until you're ready for your next brew day. Just give yourself enough time to revive it and step it up if necessary.
    – brendo234
    Mar 2, 2017 at 20:50

1 Answer 1


I haven't noticed any difference in the performance of my home-built stir plate between water and wort/yeast with one exception. I often make two-stage starters and refrigerate the flask between stages. then decant most of the old wort and add new wort. The resultant yeast slurry is very thick, and the stir plate can't turn the bar through the thick slurry. If I shake it up thoroughly first to break the slurry into tiny globs, then there is no problem.

If you want to thicken your water overall, try some flour in water, or possibly corn starch. If you want to simulate a flocculated yeast slurry, something like mayonnaise with water on top may do the job. Once the stirrer is going, the mayo should disperse in the water just like the yeast does.

  • Since you pointed it out, my main trouble in the prototype run was after it had thrown the bar and a bunch of yeast settled out while it wasn't being stirred. The thickness of the slurry at the bottom was preventing the bar from self centering, so I had to move the flask around to get it to grab the bar and drag it to the center. Shaking it to break up the slurry would've been easier, I wish I'd thought of that.
    – Simon
    Feb 27, 2017 at 16:13

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