Importantly, the described methodology is a first step toward studying fast out-of-equilibrium solutions using solid-state NMR. This approach can provide access to transient intermediates of a short lifespan. Indeed, proper freeze quenching prevents transient species from transformation and preserves their native environment, such as hydration, pH, or ionic strength. Such a native state is inaccessible with most ex-situ or isolation methods that can induce deleterious structural modifications. We demonstrated applications for biomineralization-relevant reactions, but in principle, any aqueous reaction can be studied.