Iodine shelf life

Does the iodine ever expire or go bad?
reason I ask is that it seems I may have had a bad brew with unconverted starch. The iodine test I thought showed no blue. My iodine is 5 + years old.
I've also tried looking on you tube for some good videos on how the iodine test looks when positive.

TD

I know that it does eventually go bad. I recall a 5 to 7 year recommended life. My experiance is from water purification in back packing/camping supplies. My experiance has always been with that kind of stuff is that you have time after the suggested shelf life. What makes you think that you didnt convert? Did you boil 60 mins? If all grain or partial did you have enough enzyme? Was your ABV low and if so how did you measure? Beer just too sweet, if so what was grain bill?

Thanks! I suspected as much.

Im still really looking for a nice video tutorial on the iodine test.

The particular batch was all grain either 60 or 90 minute boil, can't recall.
NB dead guy ale clone recipe.
Was using my new Brutus style brew rig and overheat the mash by accident - long story.
FG is like 1.036.

Also have a Belgian golden strong ale that finished too darn high. 1038 yeast I think i used. Long time in primary and it just never really finished. Either a yeast problem or a conversion problem.

I got no blue on either as I recall.

TD

OK.

Did a little bit of experimenting today. Got some Iodophor (Betadine) from work. Took a sample of wort from mash very early to ensure there would be starch.
Poured a small amount into a white saucer and added iodophor/betadine - NOTHING!
Unless this stuff goes bad from sitting in a hot garage, it simply doesn't work as a starch indicator.
Used the old bottle of iodine that also sits in that garage and is about 5-6 years old, and guess what, it turns very subtly blue. I think, esp in darker wort, that dilution of the wort with water will help to notice the change in color. as well as use of a white plate/saucer.
I'm looking for some "fresh" iodine now but apparently its hard to find!

Also curious about thermometer calibration. I'm getting very different reads on the PID/Temp controller than the built in thermometer on the Mash tun, a standard "lab" thermometer is closer to the PID readout and so is a digital thermometer I've got.
I think the built in blichman thermometer is off by several degrees.

TD