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## What is pre boil gravity?

Because water is evaporated during boiling, the sugars in the wort are concentrated, increasing the specific gravity and decreasing the volume. This results in a pre-boil target gravity that is lower and a volume that is higher than the post-boil values for the recipe.

## How do you calculate pre boil gravity?

Say if you have six gallons of 1.040 wort at pre-boil, and you evaporate one gallon over your hour boil. The math: 40 points/gallon X 6 gallons = 240 points. Those 240 points in 5 gallons yields a gravity of 48 points per gallon (240 divided by 5) or 1.048.

## What is the difference between post mash gravity and pre boil gravity?

Post mash is the gravity of the combined runnings from the wort collected from the mash. Pre-boil gravity reflects the gravity of the wort from the mash PLUS any additions of extract or sugars made before the boil starts.

## Is pre boil gravity before or after Sparge?

I routinely take my pre-boil gravity after sparging to determine mash efficiency so that I can throw in DME or Dextrose for a lower than expected yield or add water for a higher than expected yield, all in an attempt to hit my target OG.

## How do you calculate pre boil volume?

The formula for the volume of sparge water per batch is simply the volume of sparge water divided by the number of sparge batches, in our example 21.7 / 2 = 10.9 quarts (20.5 / 2 = 10.3 L).

## How do you find the beginning gravity?

The Original Gravity refers to the gravity of the wort pre-fermentation and the Final Gravity refers to the Gravity post fermentation. Then the Recipe Potential Original Gravity can be calculated by multiplying the GU by the post-boil volume in gal.

## Why is my OG so low?

The original gravity is too low. This can happen for a number of reasons when beer brewing, but largely because many homebrew kits call for topping off with water to get five gallons of wort, without taking into account how the brew day went. (What if you spilled some wort or didn’t get all the extract out of the can?)

## How much water boils off per hour?

Water is usually boiled off at a rate of about 4% per hour.

## When should I take OG reading all grain?

Your original gravity (OG), which is taken just before pitching your yeast and after the wort has chilled. Make sure you make any temperature adjustments to it before recording it. Follow the instructions for your hydrometer or refractometer for this.

## Is original gravity after the boil?

Is original gravity the same thing as post boil gravity.

## How do you measure mash specific gravity?

Fill your hydrometer tube about 2/3 of an inch from the top with the wash/mash you wish to test. Insert the hydrometer slowly not allowing it to drop. Give the hydrometer a light spin, to remove the air bubbles that may have formed. Read where the surface of the liquid cuts the scale of the hydrometer.