What are Stir Plates supposed to do?

[BrannigansLove]

I've not had any problems following the SNS method. I prefer the simplicity of it, and the ability to build my starter the day before I brew.

[Troutman47]

+1 for the 'Shaken, not Stirred' method.
Used it several times, works brilliantly!

[Chug]

I have been using the SNS method up until recently when I made a stir plate, it doesn't seem to make much difference to the starters, it just means I don't have to remember to give it a shake.

[Matt in Birdham]

It's a good question and always worth questioning the orthodoxy in home brewing, because as we are discovering in many areas, a lot of it is wrong, or carried over from commercial brewing and not so applicable to us.
I have no idea by what mechanism stir plates cause an increase yeast growth, but there is plenty of experimental evidence out there that shows that they do, and by quite a lot. The Braukaiser blog is always worth a read as he really gets stuck into this sort of thing - this page has some good stuff on yeast growth. The SNS method sounds good as well.

[ciderhead]

I have 3 stir plates but for the last 6 beers used sns, I had a 6-8 hour lag in the starter but an hour or 2, on the 22l.
Haven't noticed any real difference other than that tbh.

[BenB]

It sounds like it's the old Star Trek question when someone asked how the warp drives worked and the Star Trek rep said "just fine thank you"

[McMullan]

When I started brewing, I just put starters in a cupboard and forgot about them. Worked fine. The only problem was that they took days to culture. A stir plate works by keeping the yeast in suspension therefore in contact with resources needed for population growth. It works fine. YW's SNS method was originally proposed as a simple alternative for those who didn't have a stir plate. It works fine. My experiments comparing SNS vs stirred indicated no significant difference in terms of yeast cell (membrane) stress. I now use an orbital shaker, depending on volume. It works fine. My mini starters are SNS; my medium starters are orbitally shaken; and my big starters are stirred. it all works fine. Horses for courses, I guess.