Lagering question

[joehoppy]

I have read many times where people drop beer temp a couple degrees per day until at lagering temp. What is the purpose for slowly bringing the temp down as opposed to just putting it in a 40 degree fridge right away?

 

[BlueHouseBrewhaus]

The purpose of a slow temp drop is to not shock the yeast so they can continue their cleanup work while lagering. There is some debate as to whether or not it is necessary since most of the yeast work is done by then. I do a slow drop just because it doesn't hurt and may help. I have actually recorded a drop in SG of a point or two after lagering so maybe they do get a little work done in their semi-frozen state. Others can probably give you a more scientific explanation.