Starter: how long to keep on stir plate?
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Stir Plates and Growing Brewing Yeast Quickly
A stir plate is a simple machine consisting of a base which houses a motor with variable speed control. Fig 1. This motor is used to spin two precisely spaced magnets, which in turn will spin a magnetic stir bar inside your flask. The intent here is to use this stirring motion to:
Some home brewers believe that as long as the starter is moving there is sufficient opportunity for the head space oxygen to diffuse into the starter beer and become available to the yeast as a nutrient. I never really believed that. Last week’s experiment showed that yeast growth does benefit from increased access to oxygen. So, if yeast growth is a reflection of the amount of oxygen taken up by the starter, then the impact of stir speed on oxygen uptake can be shown by its effect on yeast growth.
Homebrew Starter Tips
A yeast starter is used to initiate cell activity or increase the cell count before using it to make your beer. The yeast will grow in this smaller volume, usually for 1-2 days, which then can be added to 5 gallons of wort.
Yeast starters will jump-start your fermentation, but you can supercharge the process with a stir plate, which uses a spinning magnet to keep the liquid in constant motion. This ensures that the yeast cells don’t settle, it keeps the cells in contact with wort while minimizing the concentration of “poisons” such as alcohol and CO2, and it exposes the starter to a regular influx of oxygen.
Make A Yeast Starter
Many brands of yeast for homebrewing are designed to directly inoculate 5 gallons (19 L) of standard ale wort (OG less than 1.060, fermentation temperature 65– 72 °F-18-22 °C). However, high gravity worts (OG greater than 1.060) or cold fermentation temps (less than 65 °F-18 °C for lagers or hybrid ales) require a higher pitch rate than can be achieved with a single pack of yeast. Making a starter culture prior to brew day is an economical way to increase pitching rate and ensure consistent results in your brewing.
Making a Yeast Starter with a Stir Plate
The stir plate does a few important tasks, namely keeping the yeast active through movement and aerating the wort. Yeast are anaerobic, meaning they do not need yeast to live, however, they do need oxygen to procreate.
Yeast Starter Kit
Hello I just happen to pick up The 4TH Edition of How To Brew by John Palmer. My questions is about the article where he talk about Yeast starter an stir-plate. He say One important consideration is that the stir-plate should only be used for the first half of the propagation, for example, 12-18 hours when assuming 24- 36 hours of total propagation Time. Now what is John Palmer saying exactly?