Stirplate Starter Question

Milhouse · 03-13-2009, 07:00 PM

So I put together my homemade stirplate 2 weeks ago, and purchased a 1000ml flask. I boiled maybe 850ml of water with 3 ounzes of DME in the flask, cooled to 70, added a vial of liquid yeast (Ringwood). This gave me the 1000ml needed. I placed tin foil on top and let the stiplate do its job. Later that night the yeast was bubbling out of the flask. I assumed I shouldn't have used that great of a volume. What volume of a starter would you suggest when using a 1000ml flask?

Nerro · 03-13-2009, 07:34 PM

If you're going to make a starter of 1 L (=1000 mL) you need the next size up which in most assortments would be 2000 mL. In your case I'd shoot for 500 mL. You can fit an absolutely ungodly amount of yeast cells in 500 mL.

Add the DME and nutrients (half a teaspoon per 1 oz. or so) in a stepped arrangement to grow lots of yeast fast. For 1000 mL one would normally recommend ~4 oz. (~100 g) of DME per 1000 mL of starter. You could use 500 mL and add portions of 1 oz. each over the course of 4 or 5 days. That way you keep the density low which helps the yeast swim around and keeps frothing down a bit. In the end you should have a nice huge amount of yeast cells and not too much icky muck to add to your beer.

Be sure to use some sterile cotton wool to close the neck of the flask. You don't want nasties floating around.

FlyGuy · 03-15-2009, 05:32 PM

You definitely don't want to reduce the size of your starter because you won't really get much yeast growth below a volume of 850 mL (fine if you just want to proof the yeast). I think your method sounds fine -- all you need are some foam control drops (e.g., Fermcap-S). That will eliminate the bubbling and over-flow out of your flask. I use it in every starter now. Magic stuff.

As previously mentioned, you will get more yeast growth if you feed it incrementally. This is a bit of a pain, but you might consider a two-step starter if you don't want to get a larger flask.