When to take measurements

I've been brewing for quite a few years and love the BeerSmith program.  I'd like to know when do you take the measurements for end of running gravity, post mash gravity, and pre-boil gravity?  Like to start working on efficiency and getting more out of my beers and never really understood when to take these readings.

I brew 5 gal all grain batches and fly sparge.

Thanks

End of running gravity only really matters if you are fly sparging.  I do also use it for recording the gravity of my second runnings when doing a batch sparge.  The time to take it is at the very end of the sparge step just before or after you have hit your target volume in your boil kettle.

Post mash gravity I take as soon as I have all the wort in the boil kettle and before I add any sugars or extract to the kettle (if the recipe calls for it). 

Pre-boil gravity reading is with the sugars and extract added to the boil kettle.  If you are not adding any fermentables to the boil kettle other than the wort collected from the mash, then the readings post mash and pre-boil should be the same number.

For me, I like to have a lot of readings so I take a first running and last from the first batch then the same for the batch sparge then stir the kettle like crazy and measure the preboil.    I will also measure at 30 minutes and 15 left in the boil to assess where I am in regards to my target OG.  I only measure my final gravity when I keg.

Most folks I know simply measure the pre-boil once the kettle is at the starting volume. 
Next is after chilling and before adding yeast.
Lastly, post fermentation when they are kegging or bottling.

Pre-boil gives Mash efficiency.  This is a critical value for BS to calculate efficiency and estimate late values.

After chilling indicates you concentration efficiency (not really an efficiency) of the boil.  This is generally very predictable if you boil-off rate is correct. 

The first two help you adjust your equipment profile to better predict gravity and volumes.

Finally, the terminal gravity indicates the efficiency of the yeast.  If you are accurate on the cell count and yeast age, you can predict the final gravity.  The measurement shows how well the yeast performed in they attenuation range.  most strains do not consume all sugars.  You can expect 70%-80% on a lot but each is different.  this value is already in the yeast inventory item in BS3.  You can adjust the value based on your experience in your "brew house"

Oginme said:

End of running gravity only really matters if you are fly sparging.  I do also use it for recording the gravity of my second runnings when doing a batch sparge.  The time to take it is at the very end of the sparge step just before or after you have hit your target volume in your boil kettle.

Post mash gravity I take as soon as I have all the wort in the boil kettle and before I add any sugars or extract to the kettle (if the recipe calls for it). 

Pre-boil gravity reading is with the sugars and extract added to the boil kettle.  If you are not adding any fermentables to the boil kettle other than the wort collected from the mash, then the readings post mash and pre-boil should be the same number.

Click to expand...

This right here should be a pinned post. It clearly and concisely explains some Beersmith settings that confuse (or at least creates questions for) a lot of users.

Y'all are most kind and appreciate the info.  Kevin is right as novice users do not know when to take these readings.  Might even be a good podcast.

Thanks again