Gravitie, cannot get my head around the terms

[UdonPete]

Getting mixed up on my Gravities :-

Is the Original Gravity the same as Post Mash Gravity i.e. before the boil ?
If so when is the Pre-Boil Gravity taken?
The reason I ask is Brewfather has 2 different reading for OG and Pre-Boil

Thank you

 

[schmurf]

Original gravity is the gravity of the wort post boil at room temperature. Pre boil gravity is just that, gravity before boil, but sample being chilled to room temperature.

 

[UdonPete]

Thank you, so the Original Gravity is (just) before one adds the yeast?
Also is the Original Gravity the same as Post Mash Gravity?

 

[schmurf]

Yes to before adding the yeast.

Preboil and post mash gravity would be the same in most cases. If you add something fermentable in between the mash finished and boil starts it won't be the same of course.

 

[UdonPete]

Many thanks, that's cleared that up