William's Brewing stir plate

Anyone on here have the stir plate from William's Brewing? http://www.williamsbrewing.com/STIR_STARTER_P2520.cfm

I've been using it with great success for my starters, and it's more than $100 cheaper than any other commercial product I've seen. The other day I somehow cracked my @*!&^% Erlenmeyer flask and was thinking of buying a bigger replacement so I can make lager-size starters (it was a 2L flask). But on their website it says the plate isn't suitable for flasks > 2L.

Just wondering if anyone's had success with this product on bigger flasks.

Almost positive it's the same as this one, which I own and which works well. Absolutely no frills, but you don't need any. Pretty sure Dan's a vendor here, I'd assume that if you buy direct from his site he makes a couple of dollars more than if you buy through Williams.

Thanks. I already own the stir plate, and that does look identical to the one sitting in my basement His photos definitely show active yeast, but it's kinda hard to tell if it's really doing the whirlpool action and sucking air down. Guessing from your comment, it does? Otherwise I might as well just walk around shaking the thing.

Docjowles said:

Thanks. I already own the stir plate, and that does look identical to the one sitting in my basement His photos definitely show active yeast, but it's kinda hard to tell if it's really doing the whirlpool action and sucking air down. Guessing from your comment, it does? Otherwise I might as well just walk around shaking the thing.

Click to expand...

A stir plate only needs to stir the wort and keep it moving in order to be effective. A strong whirlpool vortex isn't necessary at all and some claim that high speed stirring can be harmful to the yeast. Shaking or swirling the flask manually does work, but IMO you can generate more yeast in a shorter time frame with continuous stirring.

the_bird said:

Almost positive it's the same as this one, which I own and which works well. Absolutely no frills, but you don't need any. Pretty sure Dan's a vendor here, I'd assume that if you buy direct from his site he makes a couple of dollars more than if you buy through Williams.

Click to expand...

I just got my new stir plate from Dan yesterday. I bought on eBay, not thinking that Dan was a vendor on here (D'oh). It's much better than the one I made and cost me less than the parts I used to make mine. I tried it with water and it works fine. +1 on Catt22's comment about just stirring the yeast. You don't need a vortex. If you use an aquarium as your model, you only need to ripple the liquid at the surface to introduce O2 into it. The O2 is what the yeast need to grow.

3 Dog Brew said:

I tried it with water and it works fine. +1 on Catt22's comment about just stirring the yeast. You don't need a vortex. If you use an aquarium as your model, you only need to ripple the liquid at the surface to introduce O2 into it. The O2 is what the yeast need to grow.

Click to expand...

Your aquarium comparison demonstrates the principle very well. The gas exchange (O2 in & CO2 out) happens primarily at the surface of the liquid. Stirring continuously exposes fresh wort to the surface and optimizes the exchange rate. A vortex strong enough to suck air down into the liquid would increase the effective surface area to some extent, but not by much. So long as you keep the liquid mixed and moving, the CO2 will leave as fast as the yeast produce it and the O2 will be absorbed as fast as the yeast consume it. At least this is what I think is going on. I could be completely wrong. That has happened more than once before. The only thing I can say for sure is that my yeast seem to be very happy using only gentle stirring. Either that or they are putting on a very convincing act.