This is a brewing tool to take your home brewery to the next level and it's fun to use. Many home brewers don't pitch nearly enough yeast. A stir plate helps you culture higher cell counts of healthy yeast for quicker fermentation's, lower risk of infections and better tasting beer. All in less time than it takes to make a conventional yeast starter.
Most home brewers buy liquid yeast in the so-called pitch able tubes or smack packs. Yeast in this form generally does not contain enough viable cells to achieve the pitching rates required for successful fermentation's. As a consequence, most home brewers chronically under pitch, perhaps by a factor of 20! Good brewing practice calls for a count of one-billion cells per liter per degree Plato. For a standard 5-gallon batch, this means you should be pitching in the neighborhood of 200 billion cells into your cooled wort. Higher gravity wort's and lagers require even higher cell counts. A starter becomes necessary for a number of reasons:
- Poor storage temperature control and using yeast close to its use by dates diminishes the viable cell counts in a liquid yeast product.
- A starter will help you proof yeast by allowing you to visually determine if the yeast you purchased, maybe a month, ago still has enough viable cells for fermentation.
- Low pitching rates may result in infected finished beer, higher than normal final gravity, excess production of objectionable flavors caused by fusel alcohols, esters, di-acetyl and sulfur compounds.
- A starter allows you to step up the cell counts to the appropriate level for the style you are brewing. As wort gravity increases, the need for more yeast increases also.
The advantages of using a starter:
You are pitching a known, viable yeast culture
No anxiously waiting for up to 3 days for your yeast to “take off”
Because the yeast takes off immediately, there is less chance of infecting your wort and less chance of producing a bad batch of beer
You produce a cleaner, high quality beer
Lagers finish up to one week sooner, ales finish up to three days sooner