iodine test for starch converstion in AG batches

This is a verbatim PM I sent to BeeGee. He has a theory, but isn't sure if it's the Right Answer, so I'm throwing this to the wolves....

-walker

after another message from Billy, I think I might be confused about the term "efficiency".

Is that describing the conversion of starch into sugar, or is it describing the extraction of the sugar form the grainbed? (ie; ALL starch converts to sugar, and effeciency is a measure of how much of that sugar you extracted into your kettle.)

AG retard,
-walker

Walker said:

(ie; ALL starch converts to sugar, and effeciency is a measure of how much of that sugar you extracted into your kettle.)

Click to expand...

You got it.

I have actually come across multiple definition of efficiency:

(extracted sugar) / (maximum extractable sugar) and
(extracted sugar) / (amount of grain used)

The latter seems to be common in German brewing literature and is called Sudhausausbeute (brew house efficiency). And yes wre have pretty long words in German.

Kai

ok. thanks for clearing that up.

The yahoo's can take this thread and run it into the weeds now.

-walker

Walker said:

The yahoo's can take this thread and run it into the weeds now.

Click to expand...

yes! my time to shine!!!

i think enzymes are a government conspiracy!!! they're not real!!!!!

King Kai said:

yes wre have pretty long words in German.

Click to expand...

Yes, you do, but the beauty is that you can almost always create the word you need (if you don't know the 'proper' word) by stringing together a bunch of small words that you DO know to get your point across.

That's what I LOVE the german language.

For those of you who think German is a guttoral, spit-filled language.... you obviously have never heard much DUTCH spoken.

Walker said:

Yes, you do, but the beauty is that you can almost always create the word you need (if you don't know the 'proper' word) by stringing together a bunch of small words that you DO know to get your point across.

Click to expand...

We definitely have many concatenated words for which the English language has just a single word. But the concept of concatenated words is not foreign to English either, but there you keep a space between the words, which doesn't make the word look like one long word.

Kai

Iknowwhatyoumean.

Oh yeah...just for my edification. So we're saying that all starch gets converted to sugar if the iodine test is negative, but the efficiency is measuring how well you lauter the mash? Is poor efficiency then attributable to factors such as bits of converted starch getting stuck inside uncrushed/poorly crushed grains, just not getting sparged into solution, or get missed due to water channelizing and missing them?

BeeGee said:

Is poor efficiency then attributable to factors such as bits of converted starch getting stuck inside uncrushed/poorly crushed grains, just not getting sparged into solution, or get missed due to water channelizing and missing them?

Click to expand...

yes, and 100% efficiency would not be goo since you have to do so much sparging, that you get tannins from the husks.

One of the parameters that are measured for malts are fine grain extract and coarse grain extract. For fine grain extract the malt is ground to flour, mashed to full conversion and then all the solid are removed. The extract is measured and expressed as % of the initial grain weight.The same is done for coarse grain extract, but here the malt is just crushed. This all is done in a laboratory setting.

here is malt info from a German maltster (Durst Malz): http://www.durstmalz.de/pilsnermalt.html

There you see Fine Grind extarxt and Fine Grind / Coarse Grind difference.

Kai

Question with respect to conversion. I just finished my first all grain batch. The water that had just filtered through the grain at the end of the sparge had a very slight sweet taste. Is this normal or does my sparging technique leave something to be desired? Also, and perhaps this is a stupid question but how do you determine the percent conversion. I assume that the more sparge water you use the more sugar you extract and if you have an excess of water in the wort you can always boil it down, assuming you have a big enough boit pot.

David

davidkrau said:

The water that had just filtered through the grain at the end of the sparge had a very slight sweet taste. Is this normal or does my sparging technique leave something to be desired? Also, and perhaps this is a stupid question but how do you determine the percent conversion. I assume that the more sparge water you use the more sugar you extract and if you have an excess of water in the wort you can always boil it down, assuming you have a big enough boit pot.

Click to expand...

The last run-off will be only slightly sweet since there are less sugars left in the grains to be extracted.

I'm not sure how to determine the percentage of conversion. You may want to try to gauge the intensity of the iodine reaction. But I don't really see a need for measuring the percent of conversion.

Yes, the more sparge water you use the more sugar you will extract. But there is a point when you extract very few sugars, your PH has risen above 5.8 and you are starting to extract unwanted tannins from the husks. That's why you should stop sparging as soon as the run-off gravity is below 1.008 or the PH is above 5.8 or you have enough run-off collected to hit your gravity within a reasonable boil time. For me it is usually the latter.

If your efficiency is in the 70s, you are just fine and I wouldn't go crazy about improving it. (grains are cheap)

Kai