Processes for preparing N,N,N-trimethylethanolammonium hydroxide (choline hydroxide) and the choline hydroxide produced are described. These processes minimize the production of byproduct mono-ethoxylated and di-ethyoxylated choline in the product choline hydroxide. The processes generally include feeding ethylene oxide, trimethylamine, and water into a first reactor to create a first reactor product under temperature controlled conditions. The product of the first reactor is fed into a second reactor to form a second reactor product under uncontrolled, adiabatic, conditions. Finally, any unreacted trimethylamine in the second reactor product is removed to form a final product comprising choline hydroxide. Additional reactors can be used for the ethylene oxide and trimethylamine reaction.