My wife keeps my yeast as frozen stock in her laboratory. With a few days notice, she pulls a loop from the frozen stock and reinstates them in an agar plate. From there, she scrapes the yeast from the plate to a glucose vial.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgH350zUkQfSahbFmymbX6zv1ZwWy-mdwDwFGFcWG2EZQ0Rj98Pn2mSsGL9t3Jdk217VvWDhZ63-hhgMbBS98i_A2cJUqEa5v8YDY7xY2KJiYbNzFlnlGokpoxNzlR1TloZDhKeKJPIKR0/s320/IMG_5497.jpg)
In two days time, she brings home the vial to step-up to a 1L starter. This time, she also brought home the yeast plate to scrape for more cells.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLhfkQn6t26vSgcIrbqr2RChRdKyrWYCpxnXrvL-ogcNk5XUzgg8o-O3HivGm1bma7FaZc9UlioXQ4Ag5UpJRV4A_beA8S8CPkKSYt5xM4fSPu7leEDcsY_E_zcgbl9sqcwby5V4TZb4s/s320/IMG_5499.jpg)
Not many homebrewers have a PhD in the house to do this kind of stuff. It certainly saves cost per batch and it is very convenient!
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhyPPDWNXDf9ePp9eThtL-ytBNs28QNA_2heNCeeCCFy_wnVKbKeJlraIUQZsMD75-8wzyZ2INEtnNe7fEeatLDGkz9ItZUTCaB-giLnenh0i1K0pseko7hX6lutT57bTUeJ1oZcxC-XBA/s320/IMG_5500.jpg)
I use a wide-mouth 1L erlenmeyer flask to step-up the yeast count and increase viability for pitching. In the flask are a few hop pellets, a pinch of yeast nutrient and a magnetic stir bar. The wide-mouth flask and a few hop pellets help reduce the chance of a boil over. In a measuring cup is 1/2 cup of dried malt extract and filtered water. I warm this up to near boiling in the microwave. This also helps reduce the chance of a boil over.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh35yy3hs1MSWGKEHj-vhujmRjaTDnMib3kdntbS8N2m4tTsg8DEstYZM-Q2uJ6r0_SZRCQaegng-wME9TW7S7V1IZsSMyulWdImIDGhK5sSeRV45G-tBY_nGRWXCG3FSqY82lF4VnuH-w/s320/IMG_5501.jpg)
Together, I find 850ml to work best. 900 gives me less time to take preventative measures if a boil over is occurring (are you getting the theme here yet?). The largest challenge is bringing it up to a boil very carefully. When the wort begins to boil, ease off the heat to medium and allow to boil for 20 minutes for sterilization. (
Excuse our gross college stove! I'm sure a little of that comes from boil-overs from yeast starters but mostly from my lovely makinamess wife!)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsfXVIy3h6h0F8M57fIPGKjS3Zz5aiw4edEu0OM2g3CLNHtqW6m1j-0_iU9RuURm9GRE9rSxbrGN6IkLRsI-mR61SE6gl5fw91ceCa1fv6Ez274yDqUZgERYe7x-d4HMq4oUQTlo1ZTGs/s320/IMG_5506.jpg)
After 20 minutes of boiling, I immediately cover the flask with aluminum foil and allow to cool on the stove top for about 5 minutes. I then immerse the flask in cool bath of water until room temperature.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyUmADRrCumbNbhU54PZ2aIq87V5gM-eVKO73Urli4ekB4Agc3iptehXvFzIq9t9ann7FcoRSelp8MF5BRxzBV5ZBQLPNqKGC-czGww2cCm-HeAzxIXFbYxAjnXBd6nl9uQUM-liaAb7Y/s320/IMG_5507.jpg)
When the flask is room temperature, I pitch the entire contents of the yeast vial in the flask and allow the stir plate to provide oxygen and consistent yeast-to-sugar contact.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh38YuRcILVnoToGFomkQIfot6YMKvhWwHx1KT7Y_kzp0neqrcsLrb5eWRfZK8Q0li0-ARjw51hLrK4LTmEepnKWAVuOEH_vMvrf3ge7F9uXeP3wL3Ftpq1gFNaNex5A741nOy1XUxdD8g/s320/IMG_5510.jpg)
24 hours on the stir plate turns the starter color from a malty brown to a yeasty beige, ready for pitching and immediate fermentation. I always place a damp towel between the starter and my stirrer since it generates a bit of heat.
you don't have a Ph D in the house just yet, don't jinx it!
ReplyDeleteMaybe I should!? That way, I ensure laboratory yeast stock for years and chillindamos for ages.
ReplyDelete