Craig, Tannins are also bitter as well as astringent. Thus we can "taste" tannin, though bitterness perception is quite variable among tasters. I have been participating in a academic wine discussion group with other scientists where we have been doing a number of experiments with acid perception. One of the surprising discoveries for me was that acid solutions at concentrations found in some wines can be astringent, similar to tannin perception. My perception of the 88 burgundies I have in my cellar, (Chevillon, Maum, Boillot, Rossignol) has been that most are very astringent and unevolved still. I had assumed that the astringency was due to high tannin levels, but now, in light of Claude's and others comments here, I will revisit the wines and see if its high acidity. My personal palate preferences are for higher acidity in wines, though if the wine becomes "astringent" due to the acidity, I would continue aging it hoping it would "mellow" in the cellar. BTW, thanks for the link to this board. How long has it been around?