Preboil gravity is the specific gravity at the start of the boil. OG is the specific gravity at the start of fermentation. FG is the specific gravity at the end of fermentation.

## What should pre-boil gravity be?

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 know if gravity is pre boiled?

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 Post boil gravity?

Post boil gravity and OG are the **same thing**, barring you change the gravity by adding water or something else to dilute the wort either in the kettle or in the fermentor. OG is original gravity; meaning the gravity before the ferment.

## What is pre-boil?

(ˈpriːˈbɔɪl) verb (transitive) to boil (food etc) before ( **cooking, roasting**, etc)

## 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).

## What if my original gravity is too high?

If the gravity is too high, **dilute it by adding boiled or sterile water**: This time we’ll assume our target was 1.056 but we overshot and came in with a gravity of 1.064, again using a 5 gallon batch. We’ll use the fact that the number of points times volume should be a constant to do the dilution.

## How do you adjust the original gravity?

To increase the specific gravity of wort: Add corn sugar/invert sugar/ to increase the gravity. To calculate the amount needed, take an initial gravity reading, **then subtract that from the specific gravity you wish to begin with**. The difference will determine approximately how much sugar to add (use table below).

## How much does sugar increase gravity?

**14.2 ounces of sugar in 5 gallons of must** (or wine) will raise the specific gravity 0.005 units.

## How do you find original gravity?

Before you can get an OG, you must get **an SG (specific gravity) reading by using a hydrometer or similar instrument**. The SG compares the density of the beer (or wort) to the density of water. Water has a specific gravity of 1.000. When grains for the wort are added, the density increases.

## 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.

## Why is my original gravity lower than expected?

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 do you measure mash 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.

## What does pre boil size mean?

For low-gravity beers, with a light grist, the brewer may need to add water to reach a reasonable pre-boil volume. Reasonable meaning **a volume of wort that can be boiled for 60 to 90 minutes** and yield the expected post-boil volume.

## How much wort do you lose in the boil?

You’ll lose at **least 1 gallon in a 60 min boil** and if its a hoppy beer you can lose up to another 1/2 gallon or more to hop absorption and trube.

## 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).