AG Brewing and Gravity??

[dunard2]

Hi, all. I'm slowly starting to make my transition from extract to AG. I was reading Palmer's book last night and had a question that I thought you fine folks could help with.

In my extract experience, I take my original gravity reading before pitching my yeast. Nice and simple.

In AG, do I use the pre-boil volume as my OG mark, or do I still do it just before pitching the yeast for purposes of tracking fermentation and calculating ABV?

Is the pre-boil gravity only used to measure efficiency?

 

[Homercidal]

Pre-boil is used to measure mash efficiency. Post boil is used for fermentation Og.

Knowing your efficiency can help you dial in a recipe and make the brewday more predictable and easier. It can help identify if you can improve your brewing methods or equipment to hit a nice, reasonable efficiency (70-90%) rather than waste grain. Some people are content to brew at less than 70%, but personally, I think it ought to be easy to reach 75-80%, so why not do it?

Preboil can also be used to predict your OG based on boil off calculations. I don't' usually do that, since I can boil longer if I'm low, or add water if I'm high.