incomplete starch conversion

[Biergarden]

I had a very difficult time with starch conversion yesterday and ended up boiling the wort without a 100% conversion. I'm not sure where the problem fell, but I kind of want to consider the French Pilsner malt I used. I can't imagine that it didn't have enough diastatic power to convert in this day and age, but maybe that had a hand in things. To be sure, 25% of the grain bill used Vienna malts as well. The brewing water is rainwater and I added tsp of gypsum for a ten gallon batch (usually I add 3 tsp). After two hours mashing I ended up decocting about a gallon to raise the temp back up to working temperature, let it go for another half hour and then threw in the towel and boiled 13 gallons down to ten gallons (1.054 og), cooled and pitched. The wort was tasty and has a nice golden color with a bit of orange from the Vienna. Any thoughts??

 

[SpeedYellow]

Why do you think you failed to get full conversion? Presumably you did some sort of test. Personally, I've given up on the tincture of iodine on chalk, because of too many false positives. IMHO that test just doesn't work.

 

[Biergarden]

Why do you think you failed to get full conversion? Presumably you did some sort of test. Personally, I've given up on the tincture of iodine on chalk, because of too many false positives. IMHO that test just doesn't work.

I use iodine on a white dish to ensure I'm done mashing. I do it with every batch to see when I can start the sparge. This time, without any goof ups on my part, I didn't get a full conversion. I want to blame the malt, but I'm just not sure. I saw some improvements as time went by, but almost two hours of mashing was getting old.
I really should have checked the pH at that time. That might have told the story a little better.
Oh well, I'm fairly sure it will be a good beer anyways. THe wort smelled and tasted great. I'll post a pic next month when I finally pour the first pint. I'm guessing it will be overly cloudy.

 

[Qhrumphf]

Sometimes continental Pils malts can actually benefit from a protein rest, where US and UK malts they end up being detrimental. Can't say I've used a French Pils malt, nor am I familiar with the degree of modification, but I may have been a fairly under-modified malt. I doubt that the diastatic power was the problem, as Pils malts are usually very high, but perhaps starches were still bound up with proteins or something.

 

[Biergarden]

Sometimes continental Pils malts can actually benefit from a protein rest, where US and UK malts they end up being detrimental. Can't say I've used a French Pils malt, nor am I familiar with the degree of modification, but I may have been a fairly under-modified malt. I doubt that the diastatic power was the problem, as Pils malts are usually very high, but perhaps starches were still bound up with proteins or something.

Thanks for that. I like talking about beer.