Made the big leap today went all grain after not brewing anything at all in over a year and a half. I moved to a new house and the stove here is pretty old and unrealible. I used the 10 gallon rubbermaid round cooler with stainless steel braid as my mlt. I purchased one of the 40 quart aluminum pot from royal restaurant supply. I used my new sq-14 that my sister in law got me for christmas. Thnigs went well hit my mash temp of 152. It was only like 10 degrees out and pretty windy after a 60 min mash I lost only 2-3 degrees. I had some excessive boil off (like 2.5 gallons) might have been the temp out side combined with trying to get used to brewing on the sq-14. Not really worried about only having like 4.5 gallons in my carboy but, I start school again and today was my last chance to get a brew session in for a while. How much does outside temp have to do with boil-off?