Mash Temperature Question

I mashed in about 1/2 hour ago. Since this is only my fourth AG brew, I am still getting comfortable with my setup. Last time, I think that I mashed at too high a temperature because I ended up with a beer with a very high finishing gravity (1.019 or so). For today's brew, I wanted to get the single infusiuon mash temperature down to around 151 or 152.

I missed by a few degrees and it is mashed in at 149. I would add bit of hot water to raise the temp a bit; however, my tun is completely full with 14 lbs of grain and over 4 gals of water. (Yeah . . . I need a bigger tun )

Will my wort be too fermentable? Will I end up with a really dry pale ale? Here is my recipe . . . .

"Big" APA

12 lbs. 2-Row
1/2 lb Crystal 10L
1/2 lb Crystal 40L
1/2 lb Carapils
1/2 lb Wheat
1 oz Chinook (60)
1 oz Centennial (30)
0.5 oz. Cascade (30)
0.5 oz Cascade (2)
1 oz Cascade (dry hop)
Safale US-56

It should be quite fermentable and perhaps dry, but I don't think it will be a big difference from 151. If you're concerned about it you could always draw off a gallon or so (I don't know exactly how much) and boil it, then add it back. Essentially a decoction.

If you don't have conversion at 45-60 min, pull about 6-8qts of thin mash and boil it. (decoction like the Baron said). Then add this back to get the temp to 158F...162F (don't mix in everything at once to keep you from overshooting the target). Hold it there until you have conversion and you are done.

Effectively you will have done a 2 step saccrification rest.

Kai