From Snow Performance FAQ..
10. Can I use pure methanol?
While all components of Snow Performance systems are designed to be able to handle pure methanol, it is not recommended for a number of reasons.
• Safety: Pure methanol is easy to ignite and burns with an almost invisible flame.
• Performance: Water absorbs twice as much heat as methanol in the intake and inside the combustion chamber. Water cannot be flash-ignited, so has what is almost an infinite octane number. In the government studies for WWII piston-powered aircraft, 50/50 water-methanol was found to be the best fluid to use for auxiliary fluid injection.
• Tuning and Engine reliability: Injecting 50/50 water-methanol will prevent over-injection. If too much is injected, it will quench the flame front and the engine will bog and lose power. If too much straight methanol is injected, this will not happen, as methanol is very forgiving of rich mixtures. This could instead lead to explosive backfires, cylinder wash, etc. which will not happen when 50% or more water is in the mixture.