So I was boiling my wort last night on what is to be my fifth batch of homebrew. This is a smaller test batch, meant for a 2 gallon fermenter. I started with 2 gallons of water, steeped my grains and some pumpkin for 30 minutes, removed the grains, added 2.65 pounds of LME and brought to a boil. Waited for the hot break and added 0.6 ounces of Hallertau and set the timer for 60 minutes. Everything was going fine until about 9 minutes left in the boil when what looked like another hot break was happening, only this time, with only a little more than a gallon of volume left in the kettle, it foamed up to nearly fill my 5 gallon kettle. I stirred it back down and lowered the heat a tad to get it under control and finished out the hour. Any guesses what caused this and what the result may be?