Is my Mash Tun Large enough?

I plan to brew my first 10 gallon Batch. I have a 48 quart Rectangular Ice chest Mash Tun with a copper manifold. Will a 28lb grain bill fit? I usually mash at 1.25 quart/lb. and batch sparge. Beersmith shows 36 quarts mash in.

I think I can do it, but I will probably have to mash out at less than 168º in first runnings due to limited space - or do a fakey fly sparge to get the mash out temp up.

Would you attempt this?

Hell Yeah. How you going to know if it works if you dont do it. Instead of mashing out low why dont you batch sparge it twice. Hotter each time, will that work.

Yeah, probably no choice - I usually mashout at 160-165º, then 2 equal sparges at around 170º.
Since I am mashing my IPA at 150º, it will take quite a bit of boiling water to get the temp up to 170º range.

I fear I will lose a little efficiency - should I bump up the grain bill a tad?

You could add the 36 quarts of water to the cooler and then determine if there will be enough room for the grain before you try it. That would be playing it safe and you could then use the water for the mash. I think that is the way I would go if I was unsure.

Check out the "can I mash" it calculator here. Looks like you will be able to pull it off if you go with a 1qt per pound water to grain ratio.

Great calculator. Looks like I will be very close. I will start at 1.0 quart/lb, add the grain and then thin down the mash based on whatever room I have left in the cooler. Maybe I'll go 3 equal batch sparges to get all the sugars out.

Thanx