(WSJ) - After the binge follows some moderation. Every spring, top Bordeaux producers sell their latest wines in the en primeur market when it's still in the barrel, two years before bottling and delivery. The past two years saw strong sales, driven partly by rising interest among Asian buyers. Merchants say they make up about 40% of buyers of these sought-after wines, up from a tiny fraction just five years ago. But demand for the recently released 2011 vintage has weakened sharply.