# 🍺 Top-down Brew: Carbonation With Sugar After Pressurized Fermentation

Purpose: Determine the amount of sugar needed after a pressurized fermentation to achieve a desired level of natural carbonation.

Volume (gallons or liters)
Beginning volume of CO2 after fermentation
Target carbonation in volumes of CO2

US units Metric units

Results *** Waiting for results ***

## Notes

This determines the priming sugar needed for bottling beer that has been fermented under pressure with a spunding valve. The sugar calculations are based upon the difference between the estimated CO2 present at bottling time and the desired CO2.

The default beginning CO2 of .9 volumes is an approximate value of the amount of residual CO2 in a normal, unpressurized fermenation at 68F (20C). For pressurized fermentations, the amount of CO2 present at bottling time can be estimated from a carbonation table.

A conservative recommendation is that this approach will work best when the starting carbonation level is relatively low. Higher beginning levels of carbonation might be difficult to work with due to foaming.