The natural and recyclable gas carbon dioxide is a renowned process medium. It is easy to handle, harmless, noninflammable, available all over the world and has been used for decades in the food industry and for extraction purposes. Gas producers guarantee that their gas is 100 % recycled. Accordingly the CO2-footprint of the product is not influenced negatively.
The diagram shows the behavior of the mixture CO2 and H2O. With increasing pressure (x-axis) the weight portion of CO2 in water increases, because CO2 dissolves in water. The pH value decreases concurrently. Between 30 and 50 bar (3 to 5 MPa | 435 to 725 psi) the pH value inside the skin decreases to pH 2.8 to pH 3. During depressurization, the pH value increases again.
Accordingly, no chemicals or acids are required for pickling and basification. All you need is CO2.