Of mash temps, conversion and iodine

[pksmitty]

Please educate me. It is my understanding that mashing at a higher temp results in less starch being converted to fermentable sugar. However, when you do an iodine test, you are checking for completed conversion.

If all the starches are not converted, how does the iodine test show no more starches present in the mash? Does a higher mash temp still convert starches to sugar, just a less fermentable kind?

 

[Yooper]

Yes, the higher mash temp still converts the starches. The higher temperature favors alpha amylase, which means more long chained dextrines (sugars), resulting in a less fermentable wort. A lower temperature favors beta amylase, resulting in more fermentable wort.

Here is a great explanation: http://www.realbeer.com/jjpalmer/ch14.html