Systems Thinking and Turkey Frying

On Christmas day this year, as is the tradition at my house, I fried a turkey for the family meal.  The secret to a good fried turkey is keeping the oil temperature at a rock steady 325 degrees for the entire cooking time (about 45 minutes for a 13-lb. bird).  This is done by monitoring the temperature and adjusting the gas flow as needed.  The problem is that it takes a great deal of energy (and therefore time) to raise and lower the temperature of 5 gallons of boiling peanut oil.  Naturally as a would-be systems thinker I try my best to apply systems thinking to this problem.  This diagram I believe represents the balancing loop at play:

The rather crudely drawn hourglass on the left represents the delay between taking the countermeasure (increasing or decreasing gas flow) and seeing the impact  (a change in the oil temperature.)

So the game often goes something like this:  The oil temperature drops below the target, so you turn the gas up.  Nothing happens so you turn the gas up more.  Still nothing, more gas. Then the temperature starts to rise.  And rise.  And rise some more.  Pretty soon you're over the target so you cut down the gas.  Nothing happens, so you reduce it some more.  I think you can see where this is going.  That delay is really a problem.  As a result you can oscillate wildly back and forth above and below the target the entire time.  (So the average cooking temperature is fine, but that's no way to cook a turkey.)

It reminds me a bit of American politics in the last decade or so.  As a nation we seem to be driving our representative leadership into wider and wider swings from left to right and back again.  George W. Bush -- Barack Obama -- The Tea Party -- Occupy Wall Street.  Each an ever more extreme reaction to a move in the opposite direction.

The trick to a good fried turkey is to make fine adjustments toward the target and then have the patience to let the changes take effect.  Maybe there's a lesson there.