Stir Plates

When using liquid yeast I make a yeast starter.  Is a stir plate worth buying?  Would using a stir plate increase the cell count?

Thanks!!

I don't have a stir plate but I'll get one before I work with liquid yeast again. I'm reading Yeast by Chris White (of White Labs). Here's what he writes of starters done with a stir plate:

“There are several ways to add oxygen: intermittent shaking, continuous shaking, a stir plate, pure oxygen, or an air pump with a sterile filter. If you have a stir plate, that is perhaps the most effective method. A stir plate provides good gas exchange, keeps the yeast in suspension and drives off carbon dioxide, all of which increase yeast growth (around two to three times as much yeast as a nonstirred starter) and improve yeast health. However, there are two things to be aware of when using a stir plate. The first is that some stir plates can generate enough heat to push the starter into a temperature range that is detrimental to the yeast, especially if used in a warm environment. One small stir plate we tested added 5° F (3° C) to the ambient temperature, so you will want to account for this bump in temperature when making a starter. The second thing to be aware of is that the stir plate’s action of drawing air into the liquid can cause the temperature of the starter to mirror changes in the temperature of the surrounding air. Large temperature fluctuations in the room will result in large fluctuations[…]”

Excerpt From: White & Jamil Zainasheff. “Yeast.” iBooks. https://itun.es/us/BbALQ.l

There are many "make your own" designs on the web using a cooling fan from a computer and rare earth magnets, and a stir bar. A lot of brewers swear by them. I just swirl as often as I can while the starter is growing. Dont seal the starter with a bung, use foil so air can get in.
The ultimate goal is to have a complete yeast lab with agar slants, microscope and stir plate.

Without a doubt, based upon having done both the shaken and stir plate methods, having a stir plate will increase the number of yeast cells in a given size starter.  I got mine for free as it was being thrown out due to the fact that the heater no longer worked.  Looking at the cost of a commercial stir plate, I would have a hard time justifying the price versus the amount of gain.  Looking back at the starters that I have made this year, the cost of the DME is around $0.70/starter.  If I figured double the growth rate versus the shaken, not stirred starter, it would take around 100 starters to recoup the cost of a $70 stir plate.  That would be around 5 years for me.

On the other hand, the time saved and convenience of not having to remember to shake the starter might be worth it for you.

Thanks for the feedback.

Another vote for the stir plate!  I will also use it to step up packages of dry yeast for lagers.  A stir plate is also useful for stepping up the yeast from bottle dregs. Just make sure it is the same yeast used for fermentation.  Some breweries filter the beer then add a different yeast for bottle conditioning.

I made a stir plate using a computer fan. It worked OK for small starters but it wasn't good enough to create a gentle vortex in half a gallon. I was planning to build something better but luckily I managed to buy a professional one at a cheap price.

I made 6 gallons of special bitter three days ago and once that's out of the fermenter I'm planning a Vienna Lager using WLP838. I normally make ales but I've made a few lagers in the past. They turned out OK but they all suffered from long lag times from being under pitched. I'm hoping the new stir plate will change that.

If a stir plate is not worth buying you may see mine for sale on eBay but I doubt that will happen.

Very simple to build and you will never look back.  This pic is 12 hours after I pitched a vial of WLP001 into some 1.038 starter in a 2 liter mason jar.

Stir plate gets my vote! smaller starters and quicker cell growth. Went without one for years, now that I have one I cant believe I didn't get one sooner.