Conversion Question, If You Please...

[lsnadon]

So, for years and years, I've been doing all grain. Occasionally I strike in at 120 - 122 and rest for 15, then raise to 144 for another 15 minute rest, then raise to my desired conversion temperature, usually 150 to 155 or 156, depending on the style (bocks and some Belgians at the higher end, lagers and some British Ales at the lower end - usually I shoot for and hit 153). I do this with wheat beers or a style that has a lot of special grains. Usually, I just get the grains right to 150 - 156 and maintain it for an hour.

What I have started to wonder... while I am fairly certain that everything is converted to sugar in that 60 minutes, what happens if you "Over-Convert"? Is such a thing possible?

I'm not concerned about my 60 minute time limit to reach full conversion, I read somewhere (don't make me look thru my brewing library, please), if the starch is not converted after 60 minutes, more time won't make a difference anyway.... (any theories or evidence to the contrary?).

But again, just to sum it up, what if conversion was complete after 30 minutes or 45 minutes - will that extra time have an effect? If so, what is that effect? Good, bad, irrelevant to quality but relevant to flavors, styles, fermentation, etc?

(also, I am well aware of the iodine test, just not overly concerned with checking for completeness at this time -- wondering about "over-completeness" -- if that is possible)

 

[Northcalais40]

It is not true that all mashes will be fully converted in 60 min. I do check for conversion with iodine, and think it's fairly important to do so. I am most often going longer than 60. If you conduct an especially long mash you will have a more fermentable wort. Higher mash temps make dextrines faster, so you'll convert (and be iodine negative) more quickly. Even after this has occurred, the beta amylase will continue breaking down the longer chain dextrines into more fermentable sugar. That's why people bring up the mash temp to mash out temps, to stop further conversion.
Long story short, longer mash more fermentable wort.
If you haven't gotten full conversion after 60 min, you're not done yet.
A more fermentable wort makes a dryer beer than a more dextrinous wort (not sure dextrinous is a word).