Hi I just started my all grain smashing pumpkin and had a 2 degree difference in mash temperature. It’s currently at 150.2 degrees. Is this ok? The mash temperature is supposed to be 152 according to instructions. Also if the mash temperatuture starts out lower than expected how much additional hot water can we add to get it up to the right temp?
I would just leave it. The beer will come out a little dryer than if you hit target, but a couple degrees isn’t going to make a huge difference.
As for how much extra water you can add, that depends on how you are planning to sparge. With some sparge methods it might impact the efficiency by a small amount, though with some it will make no difference. Remember that any water you add to the mash should be subtracted from the amount you sparge with.
As far as mash out at 170 degrees, if I am mashing in a cooler, would you recommend adding hot water and then subtracting this amount from the spathe water?
If you plan to do a mashout, then adding more water to the mash will mean that you need even more water than you had planned on to get the mashout temperature to target (note: unless you are fly sparging, mashout is a waste of time, and even then the benefits are debatable). But if you do that, then yes reduce the sparge water volume by the same amount as the extra you add.
Are you batch sparging? If so, there is absolutely no reason to do a mashout.