🍺 Top-down Brew: Carbonation With Sugar with Dipstick Volume Calculations
Purpose
This priming calculator determines the amount of sugar needed to achieve a desired level of natural carbonation. The volume is calculated from dipstick-type measurements. The default values are US units for a BSG 7.5 gallon plastic fermenter at the 5 gallon mark.
Results
Notes
This calculator is similar to the basic carbonation with sugar calculator. The additional features is that volume is calculated from a dipstick measurement of beer depth.
IMPORTANT: The calculations assume that the fermenter is a cylinder with a flat bottom. The volume calculaitions will be off for fermenters with conical-type bottoms.
Start by measuring the inside diameter of your fermenter. The depth can be determined from a dipstick of some sort that touches the bottom of the vessel. Record the distance from the bottom of the vessel to the top of the beer. Use this top to bottom value for the depth measurement.
The following example is based upon the Diboshi 35l fermenter. The fermenter is 30 cm wide. A batch might be 30 cm tall. Entering these values yields 5.6 gallons or 21.2 liters.
The calculations assume a perfect cylinder. This simple approach creates a challenge for plastic buckets that have a slightly narrower bottom diameter than top diameter. The workaround is to use the average of the the top and bottom diameters. For example, a BSG seven gallon fermentation bucket is 10 inches wide at the bottom and 11.5 inches wide at the top. Use the average: (10.0 + 11.5) / 2 = 10.75. For example, the 5 gallon mark on this bucket is 12.5 inches. Entering 10.75 for diameter and 12.5 for depth yields 4.91 gallons. It's a close enough calculation.
Basic carbonation reference (volumes of CO2):
- Low: 2.0 to 2.4 - British beer styles
- Medium: 2.5 to 2.7 - Most beers
- High: 2.8 to 3.0 - American, wheat beers
- Over 3.0 - Some Belgian styles, wheat beers
The documentation and an explanation of how it works is available at this link.