Long conversion times with wheat?

[grnich]

Did an AG hefe on the weekend with about a 45% malted wheat grainbill. The starch conversion took 2 hours to complete. I'm sure I must have done something wrong. The other 55% was German Pilsner malt. My mash
temp was a little higher than usual at 158F, but I let it cool a bit to about 153F after an hour. This is my first wheat/barley AG. Plus I got crappy efficiency of 67%.

Why would the conversion take so long? Should I have stirred it more to distribute the enzymes to the wheat starch better?

 

[zoebisch01]

Wheat takes me about 90 minutes min.

 

[bradsul]

I did an AG hefe yesterday as well with 60% wheat and I hit my post-boil OG right on. Mash only took 60 minutes. This was a spur of the moment recipe and I didn't have any pilsner malt so I used 2-row, not sure what kind of difference that would make. I also didn't add any rice hulls so I was a little worried but my shiny new copper manifold worked extremely well.

Mashed at 152F and gave it a quick stir every 15 minutes. Did a 15 minute rest after adding the sparge water and running off. Wort tasted awesome and it's up in the blow off tube already (13 hours).

Edit: I forgot to mention, I got 76% efficiency.

 

[grnich]

Well brad that sounds pretty good. Maybe my Pilsner has less enzymes. I think wheat can't convert itself, but I'm not sure. Next time I think I'll stir every 15 minutes. I'm just worried about letting too much heat out.

 

[david_42]

A mash-in at 158F de-natures beta amylase completely in a few minutes, so all you have working is the alpha. They'll do the job, just takes more time.

Wheat malt has its own enzymes. In theory, you could do 100% wheat malt or even use it as a base with specialty grains.

 

[bradsul]

Well brad that sounds pretty good. Maybe my Pilsner has less enzymes. I think wheat can't convert itself, but I'm not sure. Next time I think I'll stir every 15 minutes. I'm just worried about letting too much heat out.

According to the wiki pilsner has a pretty high diastatic power (though not as high as 2-row) so I don't think that would make too much difference. When I stir I only have the lid off for about 15 seconds so I don't worry too much about heat loss. I don't lose a single degree over the 60 minute mash - at least within the accuracy of my digital thermometer, your mileage may vary.

 

[Kaiser]

Light wheat and especially Pilsner should have enough enzymatic strength to convert within 30 min, especially if you mash at 158 *F (the hotter the mash, the faster the conversion). Did you check the pH of the mash? I think your poor conversion and efficiency might have the same root cause.

If you didn't check pH can you get us the Ca, Mg and bicarbonate/alkalinity numbers of the water?

Kai

 

[grnich]

Light wheat and especially Pilsner should have enough enzymatic strength to convert within 30 min, especially if you mash at 158 *F (the hotter the mash, the faster the conversion). Did you check the pH of the mash? I think your poor conversion and efficiency might have the same root cause.

If you didn't check pH can you get us the Ca, Mg and bicarbonate/alkalinity numbers of the water?

Kai

So you don't think a lack of stirring was a problem? I gave it a good stir on mash-in. The water I used was a big bottle of bottled spring water, which is the first time I didn't use tap. I figured it must be better than tap water. Not sure of the pH.