I guess I should have started the thread with,...this is my first liquid bike. Anything liquid cooled, sold in our area, is already prepped for -40 winters. Reading your post made me wonder if your ST didn't come from a colder region dealer.According to this....
... a 50/50 mix of water/ethylene glycol antifreeze is good down to -37 C.
The user's/shop manual for my 2005 ST4s calls for 40/60 water/glycol that lowers the freezing point to -55 C, so it would appear that is is well protected against the -37 C that we see here in the northern US Rocky mountains.
I'm just going to flush it in the spring, up the glycol and see if it runs too hot in the summer. I had read somewhere that heat may be a problem with less water content in the coolant.