And trust me when I say that searching images for this word can be a bit Not Safe For Work (or your delicate stomach). Palpable is also something doctors talk about - as in, palpable tumors or bumps or cysts. So I don't recommend looking too much at those pictures!
Here's a picture I swiped from my hubby's Facebook page (thanks, honey!) of a meal he was eager to dig in to. I don't particularly find sushi palatable, but hey, he likes it...and so do plenty of other people.
When you are describing something yummy, delicious, or that will go down easy, PALATABLE is the way to go (think table, where you'd sit for some of that deliciousness.)
When you are describing something you can feel (either in reality or perception), PALPABLE is the way to go. It's a cliche, but most often I see it used as the tension in the air was palpable.