read a few posts down about a 15 minute mash. isn't there a test, maybe with pH paper, to measure that the starch/sugar conversion is complete? also, when is the best time to add the 5.2 mixture - before, during, or after the mash? inspiring minds want to know.

Add your 5.2 before the mash (to the water)
you can do a starch test ( use iodine ) to check for conversion..
Starch turns black in Iodine sugar does not... take a sample put on a white surface (plate not paper) add iodine... if you see black it is not done
BUB (boob)

The iodine test works great..........in theory. In the real world, you will never convert all the starches to sugar. You can mash for 3 days and still have a little starch. In short, the iodine test is notoriously inaccurate. You may have "complete" conversion for brewing purposes after 45 minutes or an hour, but you will quite often still get an iodine test that shows positive for starch.

My advice is to just follow standard advice about mash temperatures and times and not worry about conversion. The enzymes will take care of conversion for you, assuming you use base malts with enough enzymes to convert those grains that don't.

If you are having efficiency problems, which is generally why people think they need to check conversion, you should look first at the crush of your grains.

If you are checking conversion in attempt to shorten your mash times, you need to carefully consider the composition of the wort you will be making with a short mash time. I don't have the exact figures in front of me, but a 15 minute mash will give you something like 75% - 80% conversion, but you will have a large portion of long sugar chains that will be more difficult for your yeast to consume. A longer mash time will break down these chains and you will have a more fermentable wort.

To make a long story short, forget about the iodine test.

Wayne
Bugeater Brewing Company

In addition, a part of conversion is the breakdown of complex sugars (will pass the iodine test) to simple fermentable sugars. Outside of a lab environment, I don't know of a test for this.

Fred

If you are checking conversion in attempt to shorten your mash times, you need to carefully consider the composition of the wort you will be making with a short mash time. I don't have the exact figures in front of me, but a 15 minute mash will give you something like 75% - 80% conversion, but you will have a large portion of long sugar chains that will be more difficult for your yeast to consume. A longer mash time will break down these chains and you will have a more fermentable wort.

While I agree with you in principle bug, I disagree on the causitive factors here. Low pH will cause more fluctuations in brew house effciency than crush ever will. At pH 5.5, for example, my system drops to 67% from 87%! While at 5.2 pH, I can manage 87% efficiency (30-31.5 pts/lb/gal). Most conversion takes place ina nonlionear fashion which is asymtotic afaik. I usually and customarilty mash for 2 hours, and sparge for 2 hours, and get fairly complete conversion; but the main reason is for flavor development, which is a whole 'nother story. Ttyal, and ilbcnu!

Prost!

Michel

Someone correct me if I am wrong but if you batch sparge you shouldn't have to worry about the pH, therefore the crush will be the culprit. If I am correct too, Bug is a batch sparger.

My sparge takes about 15 - 20 mins total, I would quit if it took me 4 hours to mash and sparge. Yikes!!

BrewBum, you are partially right. Yes, I do batch sparge. I also watch my ph, normally 5.2-5.3. This, along with my fine crush, normally gives me an efficiency just under 80%. One of the advantages of batch sparging is that you don't have to continuously monitor your ph, because it only changes once or twice, not continuously. I definitely agree with you in that I would give up brewing beer if the mash and sparge took me four hours. From start to cleanup only takes me 5 - 5.5 hours.

Wayne
Bugeater Brewing Company

P.S. to Brewbum, nice to meet you a few weeks back. You suprised me though. In person, you appeared to be a nice respectable insurance agent or something, not the type of wierdo that hangs out on TBN!

ROFL

Great to meet you too Bug!! I swear, I am getting some beer out to you soon for some review!!