I always can starters to save time when preparing for a brewing session. This method makes stepping up your pitching yeast almost as convenient as simply popping a "smack-pack" of yeast. I typically can various sizes to accomodate the proccess - small volumes for initial stages, larger volumes for the final stages. Here's my procedure: First, prepare for making the starters. You'll need a fairly accurate scale (particularly for the smaller volumes), canning jars (DO NOT use "any old" jar!), lids, bands and a boiling vessel. Plus, you'll need dry malt extract (trust me: you DON'T want to use liquid...), some yeast nutrient or energizer, and a handful of hop pellets (good use for those old ones in the back of the freezer). OK! Got all your stuff together? Let's start! Rinse your jars out, the wash them thoroughly in hot, soapy water. Inspect each for chips, cracks "stars" or other signs of damage. These jars will build some pressure when being boiled, and you don't want any to explode. Also, after boiling, they develop some NEGATIVE pressure (vacuum), and you don't want them to implode, either. Any chips or irregular ridges along the lip of the jars may make them impossible to seal (so you neither get pressure nor vacuum). Best to relegate these to the garage or potting shed. They're no longer any good for canning. Put all your lids in a small saucepot, cover with water, and boil. Keep these simmering (about 180 degrees F) until ready to use. This softens the sealing material. Now you need to weigh out your ingredients. I typically make my starters 1.045. This is "middle of the road", making it suitable for most beers. Besides, since 1 pound of DME in 1 gallon of water makes a 1.045 wort, it really simplifies the math, too! Based on the contribution of a typical DME to gravity being 1.045 pg/p, we can easily calculate the weights to fill any volume and thus mix each starter in the jar. Yeast energizer is a little trickier. Typically, they specify its "dose" as 1 tsp to 1 gallon of wort - or similar. Since energizer is a dry item of varying crystal size, it is poor practice to add it volumetrically. I prefer to add it by weight. Even so, I must admit to a wee bit of chicanery: I weighed a teaspoonful of my favorite yeast nutrient and use that as my reference weight. If nothing else, it makes my nutient doping more consistent. The table below contains the weights of malt and nutrient as a funtion of volume of expected wort. Again, this is for a resulting starter of 1.045 gravity:
To determine how much energizer and malt is needed to make any volume starter, simply multiply the relevant column of the table by the desired volume. I typically also drop a hop pellet or two into each jar. For small volumes, it is sometines helpful to build a larger starter in another vessel, then fill each of the smaller jars from it -particularly helpful if making very small starters. Put the malt, a hop pellet and the energizer into the jars as you weigh them out. Add a little water, and mix, then top each up to the bottom of the threads on the mouth of the jar. Wipe the rim of the mouth off, and place a lid, seal side down. Put a ring on and hand tighten. Continue until your batch of jars is finished. Hot Water Bath Canning To process in a hot water bath, place the jars into your kettle and cover with water. Bring to a boil and maintain for an hour. Place a towel on your counter or table surface. Using jar tongs, place each jar on the towel to cool. Upon cooling you should hear the tops "pop" as a vacuum seal is achieved on each jar. Let sit until cool, then remove the rings. Wash and rinse the exterior of the jars, then store in a cool dark place until used. Starters canned by this method should keep safely for a year. Pressure Canning Pressure canning is the best method for preserving your starters. The extreme heat achieved through pressurized steam all but guarantees a sterility, and starters canned in this way will keep for many years. I've used pressure-canned starters over four years after canning them and, aside from some darkening of the wort over time, there were no adverse effects. To process in a pressure cooker, place spacer (if so equipped) on the bottom of the kettle, then place the jars on top of that. If your canner is large enough, you can usually place a second spacer on top of the first layer of jars, then add a layer of shorter jars above them. Fill the kettle with water, being careful not to go over the "fill line" engraved on the inside wall of the kettle. If there is no such line on yours, fill only 1/2 to 2/3 full. Remove the seal from your kettle lid with a damp cloth, reassemble, and put the lid on your kettle. Set the steam weight to 15 lbs, and light the stove beneath your kettle. It can take a while for the steam pressure to build in the kettle to your setting. You're there when you get an unwavering, constant "hiss" from the relief. It takes about 20 minutes to get there with mine. (You can shorten the time for the preheat by filling another pot or teakettle and boiling it in advance. Use this to fill your kettle once the jars are in.) Once you achieve your desired steam pressure, continue boiling for another 30 minutes. The longer the time, the less likely anything will survive it, but the darker the wort will be. Turn off the flame and let the pot cool before opening.
Once the pot is cool to the touch, open it and take the jars out. They should already have "popped". Remove the rings and wash the exterior of each jar before storing. Using Canned Starters To use the starters, prepare a vessel to contain your yeast. Pry the lid (an old-fashioned can opener works well for this) from one of your starters and decant it into the vessel. Whether or not you let the break material from the starter jar into your culture vessel is entirely up to you. Add yeast and close suitably (foam stopper, airlock, celophane, wahtever...) I typically can 4oz, 6oz, 8oz, 12oz, 14oz and 32 oz starters. I first pitch the yeast into a 4 oz starter. Once kraeusen has been reached, I add a 6oz starter, etc up the list. If I need to maintain a culture for long periods of time, I build it to the quart, and then periodically "feed" it 12 oz starters until I can use it. © 2000 Pat Babcock |