Pick up any wine bottle and look at the shoulder. If it's high and squared off, the bottle is following the Bordeaux template; if it slopes gently into the body, it's a Burgundy. That shape is a label inside the label — it tells you which European tradition the wine wants to be read against. The signal started out as engineering and has hardened into marketing.
Burgundy's shape came first because it was easier to blow. Early glassmakers could draw a smooth slope from neck to base without much skill; the squared shoulder of the Bordeaux bottle was harder to do consistently and didn't come into wide use until Pierre Mitchell's Bordeaux glassworks opened in 1736. By the mid-1800s the modern silhouette had settled in. The shoulder did real work — Bordeaux's tannic reds throw a fine sediment as they age, and the high shoulder traps it during the pour. The 750-ml standard itself didn't arrive until the 1970s, when the EU regulated bottle volumes; before that, capacity drifted from glasshouse to glasshouse.
Bordeaux
Burgundy's shape did the opposite job by accident. Pinot Noir and Chardonnay throw very little sediment, so the sloped bottle never had to be redesigned. Each classical region ended up with the bottle its wine happened to need. Champagne thickened its glass and deepened its punt to hold internal pressure; the Rhine valley pulled its bottles into a flute that fit barge holds. Function chose the silhouette, region by region.
Then the New World arrived and the choice stopped being functional. Cabernet Sauvignon — Femente lists more than 155,000 wines built on it, more than any other variety — goes in a Bordeaux bottle almost anywhere on earth, because the silhouette signals 'serious, structured, age-worthy.' Pinot Noir and Chardonnay go in Burgundy bottles for the same reason. The biggest tell is Syrah: an Australian Shiraz takes the Bordeaux shape to read as a power red, the same grape in the Northern Rhône takes a Burgundy to read as a Pinot cousin.
What the bottle says today is: 'this is the kind of wine I want to be compared with.' A New World Cabernet in a Bordeaux silhouette is asking to be judged against Pauillac. The closer the producer's hopes sit to the European classic, the closer the bottle imitates it. Read the shape first and you've read the producer's intent — before the wine has said a word.