# Frequent question: How do you calculate pre boil gravity?

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If the actual pre-boil volume is 7.0 gallons (26.5 L), the actual pre-boil gravity is 1.033 and boiling losses are 1.5 gallons (5.7 L) per hour, increasing the boiling time by 16 minutes will achieve the post-boil target gravity (OG) of 1.048).

## 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 calculate mash gravity?

To calculate your mash extraction in terms of ppg, you need to multiply the number of gallons of wort you collected by its gravity and divide that by the amount of malt that was used. This will give you the gravity (points per gallon) per pound of malt used.

## How much does gravity increase during boil?

In the above examples, a 9-minute increase in the boiling time will raise the OG by approximately 1 gravity point, while decreasing it by 9 minutes will lower it by approximately 1 point. The approximate change in the post-boil volume per 9 minutes will be 22 fl. oz. (640 mL).

## When should I take pre-boil gravity?

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.

## 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.

## What does Mashout mean?

Mashout is the term for raising the temperature of the mash to 77 °C (170 °F). This stops the enzymatic conversion of starches to fermentable sugars, and makes the mash and wort more fluid.

## How do you calculate initial 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.

## How do you measure beginning gravity?

Original gravity is a measure of the sugars dissolved in the water in your unfermented wort. It is typically measured with a hydrometer or refractometer in the fermenter when brewing is complete but before fermentation has started.

## How are gravity points calculated?

Gravity points = grain’s extract potential (EP) x mass (lbs) = specific gravity x volume.

## Why is my OG so low?

Sparging – If you sparge too quickly, have a poorly designed mash tun filter, or sparge the wrong volume you can get a low OG. Take your time when sparging, which will let the wort extract as much as possible from the grain bed. … For example, a 10% increase in final volume can result in a 10% decrease in OG.

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## How much water boils off per hour?

3) Boil Off / Evaporation Rate: This depends on how vigorous of a boil and the shape of the kettle. The average is around 1.5 gallons (6 quarts) per hour. If the kettle is narrow (like a keggle), expect ~1 gallon per hour, or short and wide, as high as ~2.5 gallons / hour.

## What is OG in brewing?

A gravity reading taken just prior to yeast being added, or pitched, is referred to as the original gravity (OG). The OG will provide the brewer with a good idea of the potential alcohol percentage for that particular beer.