Brews you can Use

Warning: boring tangentially beer-related geek-out (yeast culturing) ahead, mostly for my own reference.

My standard solid growth media recipe:

• 1 cup water
• 4 tbsp Malt extract powder.
• 1 tbsp agar-agar flakes
• 1/8 tsp Wyeast yeast nutrient

for liquid growth media, just omit the agar.

Mix it all up, microwave to boil, pour into tubes (about 1/4 full) and a flask, then process in pressure cooker for 15 minutes at 15 PSI. Let cooker cool down on its own, then remove everything. Prop up tubes in a slanted position to solidify. Meanwhile, let the flask of media cool, then pour into (presumably sterile) plastic petri dishes.

The tubes I use are about 1x4 cm vials. The plastic plates are about 10cm in diameter. This recipe made 16 tubes plus 5 plates the first time I tried it. Tonight, I made a half-recipe, yielding two tubes and three plates. The half-recipe probably wasn't worth it...

Other notes:

• The agar-agar flakes take a long time to dissolve, even in boiling hot wort/water. It needs more stirring, probably 3-4 times during the course of boiling in the microwave.
• I really need to look into glass petri dishes some more. Pouring plates is a hassle, and the plastic ones can't be re-used, to boot. The only glass petris I've seen in person have been the ones for sale at Ax-Man's, and they don't seem very nice. The lids don't fit tightly at all, and it's hard to pick them up to manipulate, even if you can devote a full hand to it...
• Alternatively, I may also look into pre-poured slants, plates, and starter tubes. Sure, this is a step in the opposite direction, disposable-wise, but it would save a bunch of work.

My last round of yeast culturing was very slant-centric. I only used one plate to clean up the yeast, and propagated it the rest of the way on slants. This time, I'm going to try to plate yeast out more often, and experiment with sterile distilled water storage in addition to slants. It sounds more forgiving from what I've read.

I started this all so I could maintain a supply of WLP022 Essex ale yeast outside of the short season White Labs offers it. This time, I may branch out and try to ranch the yeast from a bottle of Thomas Hardy's ale, and see if I like that for the lower gravity beers. If so, my next crack at cloning TH will most likely use the correct yeast :-)