OK, so the science geek in me came out this weekend and I have to share it. I was brewing on Sunday, outside in the yard. I have an 8 gallon megapot and a darkstar burner. My wort was in the pot and I was about 40 minutes or so into the boil. I grabbed my spoon and gave a stir causing a whirlpool. Then the magic happened. At the center I began to see a foam gathering. I thought I was going to have the beginning of a boilover. The whirlpool sucked the foam down and there was a “burp” from the center which somehow caused the whirlpool rotation to accelerate! Then the foam gathered again and the same thing happened. It went on for about a minute when I thought I had to call my wife over to see the magic. She came over and called me a geek but still was sort of intrigued. It continued to do this with some burps spewing some wort from the pot. I realized I had some kind of heat fueled system going on like a tornado or a hurricane. I had to actually put the spoon in the wort and stop the rotation otherwise it would likely have continued for the remainder of the boil. I will try and get this to happen again on the next brew day and I will take video.
It must be common as it does that with mine on almost every batch I brew.
It’s well known that stirring the wort to create a whirlpool prior to boil will avert a boil-over by sucking and whirling the proteins down the center, with the side-affect of burping wort back up the center. It’s generally best to stop this before the burps get too big and splash all over the place.
Generally speaking when it comes to brewing there’s not much new under the sun.
Glad you’re having fun though.
It must be my the brewmometer in my blichmann boilermaker but I am not able to start a very good whirlpool.