For all wines labeled 'Trader Joe's' on the front label, Cellartracker has adopted a policy of consistency with Producer = Trader Joe's.
The technical producer is usually listed at the bottom of the back label. Some producers listed are actual wineries with other own-branded wines and others are not. This producer within a particular label designation could change between vintages (and even within.) In order to provide information and make the wines easier to find, that producer name has been made a hidden search term for those wines.
Appellation also matters a lot with differentiating Trader Joe's wines.
Below is a list of the producer attached to particular Trader Joe's wine labels. Feel free to edit and/or amend as needed.
Coastal - Castoro Cellars (All Trader Joe's Coastal wines appear to be from Castoro Cellars.)
Grand Reserve Meritage Rutherford - JBA Cellars
Cabernet Sauvignon Grand Reserve Rutherford - JBA Cellars
Cabernet Sauvignon Reserve - Mazzocco
Zinfandel Reserve - Mazzocco
Viņas Chilenas - Videma
Syrah Reserve Mendocino - DnA Vineyards
Petit Sirah Reserve Mendocino County - DnA Vineyards
Pinot Noir Grand Reserve - Adler Fels
Meritage Reserve Napa Valley - Adler Fels
Moscato Late Harvest - Canyon Ridge Vintners
Vintage Ale - Unibroue
Riesling Petit Reserve - ASV Wines
Sauvignon Blanc Grower's Reserve - ASV Wines
Cabernet Sauvignon Grower's Reserve - ASV Wines
Riesling Petit Reserve Columbia Valley - Vw Wine Group
Grand Reserve Meritage Napa Valley - Maxwell Creek
Brut Reserve NOrth Coast - Rack and Riddle
Mystos - Family Nueva / Familia Nueva
Syrah Reserve Paso Robles - Family Nueva / Familia Nueva
Cabernet Franc Petit Reserve Paso Robles - Family Nueva / Familia Nueva
Grand Reserve Meritage North Coast - Our Cellars
Pinot Noir Grand Reserve Russian River Valley - Patrick Slater / Truett Hurst
Pinot Noir Grand Reserve Sonoma County - Truett Hurst