Recarbonation

Recarbonation is the process of reintroducing carbon dioxide (CO2) into a system that has lost CO2, thereby restoring or increasing its carbonation. The term is used in several disciplines to describe distinct but related phenomena governed by CO2 solubility and carbonate equilibria in liquids or the diffusion of CO2 into solids.

In the beverage industry, recarbonation refers to reintroducing CO2 into flat or partially carbonated drinks such as sodas, beer, or wine after degassing or fermentation. It is typically achieved by injecting CO2 at elevated pressure and low temperature to maximize solubility, aiming for a defined carbonation level often expressed in volumes of CO2. Quality control considers temperature, pressure, and contact time, as overcarbonation or inconsistent dosing can affect taste and mouthfeel.

In water treatment, recarbonation is used to restore carbonate alkalinity and stabilize pH after processes that remove CO2 or strip minerals. CO2 gas or carbonated water is dosed to shift carbonate equilibria and adjust pH and buffering capacity. Monitoring focuses on pH, total inorganic carbon, and alkalinity to ensure suitability for distribution and consumption.

In cement and concrete science, recarbonation describes the slow uptake of atmospheric CO2 by cured concrete, where CO2 reacts with calcium hydroxide to form calcium carbonate. This can reduce porosity and potentially improve durability, but extensive carbonation lowers pore alkalinity and can affect the passivity of reinforcement in moist environments.

Overall, recarbonation is defined by the reintroduction of CO2 to restore or modify carbonation levels, with applications ranging from product quality control in beverages to chemical stabilization in water treatment and long-term material behavior in construction.