measured post mash gravity vs measured pre boil gravity

what is the difference between measured post gravity & measured pre boil gravity? Aren't they both the same?

Measured post mash gravity is the gravity of the wort out of the mash tun

Measure pre-boil gravity is the gravity of the wort out of the mash tun PLUS any water, sugar, and extract additions

relaxed91859 said:

what is the difference between measured post gravity & measured pre boil gravity? Aren't they both the same?

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Personally for me I tend to take a gravity reading at the beginning of the boil, so pre-boil gravity reading, then at the final of the boil or post-boil gravity.  unless you are a commercial brewer trying to recreate a specific gravity and flavor profile, or just an enthusiastic home brewer, measuring gravity before boil, then again after adding adjuncts, fruits etc. seems like overkill.  The final gravity into the fermenter is what you really need for the specific gravity at the end or testing along the way to see where your ABV is sitting.

SplitHop said:

measuring gravity before boil, then again after adding adjuncts, fruits etc. seems like overkill.  The final gravity into the fermenter is what you really need for the specific gravity at the end or testing along the way to see where your ABV is sitting.

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Well, yes. But, along the way, measuring the contributions of ingredients is equally important in understanding what you're creating. In BeerSmith 2.2, measuring preboil, before the addition of kettle sugars was more difficult, especially if those sugars were added mid to late boil. You had to zero out any sugars to see what your preboil gravity should be, compared to your results, and record mash efficiency.