Apparently it isn't. This is reported from Erowid:
https://www.erowid.org/ask/ask.php?ID=2111
I've eaten blotters with and without taste..even white-on-white without any ink at all on special paper. Not that crazy ass mouthnumbing or superbitter taste, but a slightly metallic and dissipating one.
/u/ThrowAway81718 /u/dandydaniels /u/happytobelonely /u/babygucci1017 /u/BarmeloXanthony /u/trickricksick /u/KamajiTheBoiler /u/LedLevee
LSD isn't tasteless, but most people don't put enough of it directly on their tongue to find that out.