I agree about the risk of bias. If he cheated, even subconsiously, on the tap vs Soma test, the results are consistent with bottled and Soma being indistinguish

I agree about the risk of bias. If he cheated, even subconsiously, on the tap vs Soma test, the results are consistent with bottled and Soma being indistinguishable. Which is the opposite conclusion. The suspicious inability to distinguish bottled water from Soma agrees with this. He wouldn't be able to cheat on that test if he actually couldn't tell the difference, but could cheat on tap vs Soma like you said about water and orange juice. If he didn't even know which two types he was comparing, that would protect from that kind of bias. However, from the setup, it looks like he does know.