Well, you cannot un-make or change the wort you mashed at 150F - it made those types of sugars that ferment very well and they cannot be changed. Yes, you will have to mash higher for maltiness, like 155f to 158F, and maintain that mash temp. One hour is enough. Longer risks dropping the temp and losing that maltiness, unless you have some fancy way to maintain the mash temp.
a few questions:
- What size batch are you trying for?
- Did you use a one to three gallon metal pot for the mash? (I do not care if it was aluminum or stainless)
- What was the total amount of water and grain?
I am guessing you are making very small batches, like 1/2 gallon. Regular mash-tuns are well insulated picnic coolers and similar. Multi-barrel recirculating systems have active heat controllers. The original BIAB style done in a metal pot depends on a large thermal mass and warm ambient temps to maintain a steady mash temp.. A 5 gallon batch of BIAB will have 8 or more gallons of water and something like 12 lbs of grain. And this was developed in Australia where it is a bit warmer most of the time. Even so, many people swaddle the metal pot in a parka or a duvet (comforter) for insulation.
Smallest batch I have done is 2.5 gallons, ambient was 70F. It was
very difficult to maintain the mash temp in an uninsulated pot. I kept turning on and off the electric stove. Other things I tried: wrapping in an old winter coat, wrapping with a comforter, placing in the oven (minimum is 170F, so I heated it to that temp, turned it off, put in the pot) I melted part of the coat on the stove.
Now I have an 8 gal pot with 2 layers of Reflectix on the side and 1 on top. Even so, it helps if I swaddle it in something. And don't forget heat loss from the metal bottom! My last batch I removed it from the stove and put it on folded towels.
Try experimenting with maintaining temp with
plain water. When you can do that, then apply the same methods with the mash.