Thanks for the tip. Someone on rec.crafts.brewing said the same thing just now and there is a link on the wiki page to a university web page showing the colour changes.wessmith said:Sosman, pleased to see someone observing the conversion process. However you are missing the main show due to the intensity of colour in straight Iodine. Dilute it 50:50 with distilled water and you will be able to see more of the subtle colour changes from black thru to gold or mahogany (if your dextrins are high). At the end of your mash, there should be NO hint of blue/black colour change even when you "mash" your wort sample in the Iodine solution. This little point will also tell you how effective your crush is.