Test protocol biogas composition determination (version 2.1)

Determining the composition of biogas requires either laboratory equipment or a handheld biogas analyser. This equipment typically measures CH4, CO2, O2 and H2S in a fast and accurate way but it is expensive to buy (starting at approx 3000 USD) and need regular calibration by a certified supplier.
Somehow, this equipment is never available when you most need it.
This document describes an alternative, low tech testing method using a caustic soda (NaOH, sodium hydroxide) solution to capture the CO2 in the biogas and estimates of the water vapour contents. The principle is not new: it has been described earlier in articles on the internet1 and there are toolkits available for this purpose2. However, an accurate test using easy‐to‐find gear was not available yet.