Iodine Test

[Brewtus]

Luv a poll.

Can anyone explain how to do an Iodine test it the mash process? What do I need and what does it tell me?

 

[dr K]

What does it do: its a sort of litmus that tells you if you have any any unconverted starch.
Should you do it: If you are using modern malts and so long as they are reasonably fresh, and so long as your mash regime is pretty standard, then at least try it but you find every time your conversion is complete.
However: if you are using poor quality malt (old usually) a test is almost compulsory.
K

 

[///]

Can we ever hold Aussie Malts back???

 

[Thirsty Boy]

I'm with DrK ... Unless I do something unusual, I just get "all good" results from an iodine test, so I only bother if I am doing something weird with my mash or ingredients.

How to -

Take a small white tea saucer - use a dropper/syringe/turkey baster to suck some nice clear wort from the top of your mash (25ml would be more than plenty) and put it in the saucer - drip a drop or two of iodine liquid into the wort.

If it stays all lovely and amber ... you have no starch dissolved in your wort and therefore it has been converted by the enzymes to sugar of one sort or another. If it goes all black and cloudy .... that is unconverted starch reacting with the iodine and your mash is not yet finished converting.

you can use Iodophor as the iodine solution, then you dont have to buy anything extra.

To see the effect in action so you know what you are looking for - iodophor into water, compared to iodophor into water that you have rinsed some mashed potatoes or cooked rice/pasta in. You'll see.

TB

 

[buttersd70]

I do it the most of the time, but not all. depends on what I'm mashing, and how I'm mashing it. For 'standard' brews with 'standard' mashes, I don't bother anymore, but if I am doing a short stiff mash (specifically for increased dextrins, which is happening more often. Jump mash v2 is happening tommorow night), I want to mash only as long as required for conversion, and without iodine testing, this comes down to guesswork.

 

[PostModern]

I would only bother if:
*Malt is suspect
*Large proportion of non-malt starchy mash adjuncts
or
*New mash regime.

 

[Tony]

I did it once or twice with my first mashes but found it to be a waste of time with freshly cracked modern malt.

I say dont bother

cheers

 

[Brewtus]

Thanks guys, another brewing mystery solved.

 

[Josh]

So if I was to do a wit using a decoction for my unmalted wheat, oats and a bit of pils malt, an iodine test would be pretty handy?

 

[Yorg]

So if I was to do a wit using a decoction for my unmalted wheat, oats and a bit of pils malt, an iodine test would be pretty handy?

Sure, but as with any mash, make sure the sample is completely free of debri, as the problem with this test is that very small quantities of husk particles can give you a false positive and make your brew day longer.