Brewed Screwy's Wheat beer today

[Banjo-guy]

I had a stress free and basically uneventful all grain brew today. I actually felt like I knew what I was doing for the first time.
I made Screwy's 420 Special Wheat beer. Screwy can correct me if I am wrong but it is seems unusual because of the use of American C hops and coriander,grains of paradise and bitter orange peel. The recipe and process is explained on his web site.

I use biab and had an issue with mash temperature. I hit the 152 temp dead on. I mashed for 70 minutes and ended up at 146.
I wrap my 9 gallon kettle in a sleeping bag and cover the lid with a towel. This was an indoor brew and the inside temperature is 68. It seems like a pretty big drop to me. I only opened the lid once to put in PH stabilizer. I did that after 12 minutes.
Does that seem like a very big drop in mash temp over 70 minutes? ( 152 to 146 )
Because I am mashing 4 gallons of water for 5 lbs of grain in a 9 gallon pot I have a lot of dead air space between the top of the kettle and the wort level.
I can fit my kettle into my oven and have been thinking about trying the oven method of mashing.
I missed my pre-boil gravity of 1.050 and hit 1.040. I added dme and continued with the 60 minute boil.

This beer was my favorite beer from my first year brewing. This time I used AG . Last year it was an extract brew. I used fresh, sweet orange peel from a valencia orange last year and really liked how it turned out. This time I went with Screwy's recipe and used dry bitter orange peel.

I used US-05 which won't have as much character as Screwy's recommendation of ECY-10 Old Newark Ale yeast.

I'm going to put this one in the rotation because it was so good last year. I might change the orange peel to fresh and sweet next time.
Thanks Vince!

[Inkleg]

Does that seem like a very big drop in mash temp over 70 minutes? ( 152 to 146 )

Yes and no, the extra head space does contribute to the heat loss. I've had drops like that before. It's always made good beer.

[Brewbirds]

If you are brewing inside I would advise that you try the oven mashing for one or two batches at least to see if your temps stabilize compared to what you do now if you are losing heat.

We have great success with it for our batch size though a longer mash time, say with pilsner malt could drop the temps for your mash out unless you give the oven a boost, it just depends on what you are brewing and what your mash in needs to be.

I do not stir during the mash where some do so I don't open the oven door and release heat and so far for us we get a stable mash in/mash out temp.

I guess the bottom line is going to be based on your oven, pot size, mash time etc. but it does work for us FWIW.