Iodine Test for mash completion

[bicarb]

Does anyone know about the iodine test for checking completion of the mashing process?

Do I use iodine from the chemists?

And what colours am i looking for to check results?

If i have a combination of grains in the wort do i test each type individually?

Is the iodine test still used today or is there a more accurate method?

Cheers
Bicarb

[James L]

The iodine will react with the starch in the mash. The starch indicates that the conversion of the sugar is not complete, and therefore requires longer.

For a positive iodine test (the presence of starch), the addtion of a drop iodine to a drop of you wort will produce a black substance. It helps to do this mixing on something white so you can see it clearer.

Dont add the iodine to the mash.

For a negative test, you will see no colour change... (the liquid mixture will still be the colour of your beer, but there will be no black compound produced.

As far as the iodine you need to use, i think the iodine from the chemist should work (even though i did not buy mine from there, i got mine from work).

[Bizier]

I know iodophor works well for this, as every time a drop gets on the paper label it makes a great mess.

[Trough Lolly]

Betadine will work too...

A few drops of the wort on a clean plate with a drop of betadine added will do the trick. Don't return it to the mashtun! If there's starch present - ie, possibly incomplete mash - the solution will react and turn black. A completed mash should result in next to no colour change.

Keep the sample free of grain husk / solids as this will skew the result every time...

Alternate method? Mash in - wait an hour - sparge - done!

Cheers,
TL