My question is regarding which volume to use when calculating OG, and more importantly why.
How to calculate the gravity points for a recipe is fine, but then according to BeerSmith at least, you should divide this by the into fermenter volume, and that is what puzzles me.
When boiling, water evaporates and that will cause the gravity to go up. When boiling is done, when the solution is chilled down, it will shrink by around 4%, and this is also a part that reduces volume, while still containing the same amount of sugars, so this will also make the gravity higher. So far, all good.
But now we transfer from kettle to fermenter, and the loss here should not affect the gravity of the solution, since the loss would be both water and sugars.
So my question is then basically: why should I use into fermenter volume, and not post boil after shrinkage volume?
EDIT My question is regarding estimating the OG, not doing a OG reading when actually brewing. When measuring the OG, it does of course not matter if I do it just before or just after I transfer to the fermenter.