It occurred to me, out of necessity really, that starter wort can be made with some spare base malt on a cheaper basis than dried malt extract (DME). I had a brewday coming up, and I recall not having any, or not very much, DME on hand for my yeast starter. I had more base malt than I needed, so I decided to try a “stove top” mash-in-a-bag.. Even if you are an extract brewer, this can be done quickly and cheaply. Consider that a pound of base malt may cost you $1.25 or less than a dollar as opposed to dried malt extract, which can cost about $4.50 a lb. It is as simple as making stove top oatmeal! …easier even.
You will need:
- A big pot
- 12-16 oz of cracked (milled) base malt of your choice.
- 1/2 gal of filtered water
- thermometer ( I have a long glass lab thermometer which I bought for about $7.00 This also makes it handy to stir with it also.)
- iodine (first aid grade)
- A small white colored plate or bowl
- Crack the base malt and put it into the paint strainer bag.
- Drop the bag of cracked malt into the water in the pot.
- Heat the “cold mash” while stirring, to 150 degrees F and maintain that temp for at least 25 mins.
- After the 25 mins is up you must check for sugar conversion. Take the white bowl or plate and drop some of your wort with a spoon onto the plate. Make sure its just liquid and very little malt particles. This could give you false reading and will void the test. Now add a drop or two of iodine on the plate. Slowly merge the two liquids together.If conversion is complete, the iodine color will not change. If there are still long chains of starches present in the wort when the two liquids meet, you will see a purple tinge. The purple color means that the mashing process is not done, and you will need to continue to hold the mash at 150 degrees. Continue this step every 15 mins until you seen no change in color and the purple tinge cannot be seen. Make sure you rinse off the previous test with water to avoid false readings. NOTE: Always discard the test iodine and wort solution when finished. Iodine is poisonous and should never be consumed.
You can find more info on the iodine starch conversion test here: http://www.winning-homebrew.com/starch-conversion-test.html
In all actuality this process should not take any longer that about 20 – 30 mins. If you see that the color of the iodine has not changed you may go ahead and pull the bag out of the water (what is now called wort). Heat up the wort to boiling and boil for 12-15 mins. After the boil is complete you must cover the pot and immerse the pot in an ice bath. I usually use the kitchen sink.When the temp of the wort reaches about 65-70 degrees you are safe to pitch your chosen yeast culture into your sanitized container. This should get you an approximate original gravity of 1.050 for the final starter wort.