Yeast Starters

On July 27, 2008, in Homebrew Gadgets, Homebrewing, by Mark Ranes
Nasty Hands Covered with DME!

Hands Covered with Nasty DME!

I read a simple, yet very cool tip on a beer blog recently (I don’t remember which blog or I’d give it credit:) that makes creating yeast starters a breeze.

My personal feeling is that DME is the most vile stuff on earth.  As soon as it comes in contact with any moisture (like in the air or even your hands), it creates a nasty, pasty coating on everything it touches.  Little poofs of it go everywhere even when you just open the bag!  Jeez – I hate the stuff, but it is a necessary evil.  Anything I can do to cut down my contact time with the stuff is a blessing.

Measuring DME

Measuring DME

Basically, I just buy a bag or two of DME, pre-measure it into Ziploc bags, add a pinch of yeast nutrient, and then throw all the little pre-measured bags into a 1 gallon Ziploc for storage.  Then, when it’s time to make a starter, I just cut the bottom corner off one of the pre-measured Ziplocs and pour it into the flask – no funnel needed. I then just add water and proceed as normal.  This process means that I have to touch the DME just once – and I like that!  Why hadn’t I thought of this before?

Small and Large Pre-measured Bags of DME

Small and Large Pre-measured Bags of DME

My general process of making yeast starters is similar to what other homebrewers do, but may differ a bit because I like to “feed” my starters.  I use two flasks for making starters – a one liter and a two liter flask.  I use two-thirds of a cup of DME in the two liter flask, and add 1400 ml of water.  In the one liter flask, I use one-third of a cup of DME, and add 800 ml of water.  Each flask is boiled for fifteen minutes.  After boiling, I quick-chill the large flask in an ice bath to get it down to pitching temperature.  In goes a vial of White Labs yeast – or sometimes two, for a high gravity brew.  I like to get the starter going four or five days in advance, if I plan well.  Usually it is just a couple days prior to  brewing, though.  The large flask is put on a stirplate and the small flask goes into the refrigerator.

Boiling Flask of Starter Wort

Boiling Flask of Starter Wort

Once the large flask is on the stirplate, I put a shot of oxygen into the flask, and then turn the stirplate speed way up to get the starter wort into a froth, mixing the oxygen into solution.  I usually do this two more times in the first couple hours the wort is on the stirplate.  In general, I keep the stirplate on 300-400 rpm until it completely ferments out – usually in about twenty four hours.  If I have the luxury of three or four days before brewing, I’ll put the large flask into the refrigerator for a day to get the yeast to drop out of suspension.  This way, I can decant off much of the starter wort and then “feed” the starter again for another complete fermentation to kick up the yeast cell counts.

If I only have another day before brewing, which is more typical, I’ll add about 300 ml of “feeder” wort from the small flask early in the day.  This sets the starter off again on a quick fermentation, waking up the yeast and slightly increasing cell counts.  Finally, on brew day morning, I’ll add another 300 ml of “feeder” wort to wake up the starter and get it ready for pitching into carboys.

Stirplate, Feeder Wort and Oxygen

Stirplate, Feeder Wort and Oxygen

Throughout this process, I maintain strict sanitation procedures.  About a minute before the flask is done boiling, I put aluminum foil on both flasks, and the exposure to the air and unsanatized equipment, from this point on, is minimized.  All stoppers, stir bars, yeast vials and even my hands, are thoroughly sanitized before they are exposed to the starter wort.  Lets face it, you don’t want your yeast starter to be the contaminating agent for ten gallons of brew!

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