First Time Stirplate

Ingredients
1

Hello,

I am using my home built stirplate (standard build 12v computer fan with 2 hard drive magnets) with an Erlenmeyer flask for the first time. I tested the plate with a glass jar and a pint or so of water and always saw a pronounced vortex.

I just cleaned, sanitized and dumped in a 1qt starter and started running. I have noticed that I am not getting
the vortex that I had with the 1pt test. In fact, the starer has more of “dimple” than a vortex. The yeast appear to be in
suspension.

I bought the flask yesterday and in my excitement to get a starter going, I didn’t test with water so I don’t know what to expect.
My guess is that the 1qt starter is heavier than the 1pt test with water and the resistance of the larger volume is slowing the rotation speed. I should say that the fan speed is not restricted, it’s going as fast as it can, given the load.

Here are two pictures:

https://picasaweb.google.com/lh/photo/JSN45Xv4z3KalO1aCTJ-8Px09yX6VdNA3PV_tVK72DQ?feat=directlink

https://picasaweb.google.com/lh/photo/a7ERhj6i7AWuibqyoDV0f_x09yX6VdNA3PV_tVK72DQ?feat=directlink

Is there anything here to be concerned about ? Do I need a more powerful fan?

Thanks!

2

That looks pretty much normal to me.

You don’t need a tornado in the flask.  If you have a dimple like you say, that is good enough.  The CO2 is coming out of solution, which is good for the yeast.  You have foil on the flask, so O2 will difuse in, which is good for the yeast.  Looks as if that one is just about done and ready to cold crash in the fridge.

3

Thanks for the info.
Cold Crashing now.

4

If the foam has died down and there are no bubbles coming up, then it is time to cold crash.  The pictures say it is close (when taken), I would say another 6-8 hours from the time of the picture.  If that time elapsed, and the activity has died down, then cold crash.  Otherwise wait a little.  The yeast do not have a timetable.