The soils in Paso Robles – and at JUSTIN – are exceptionally unique because they were once an ancient seabed populated by marine life such as coral and mollusks. Over time, their skeletal fragments formed sedimentary rock rich in calcium carbonate. Just as calcium is an important mineral for strong bones, it also plays a supporting role in the story behind Paso Robles wines.

These limestone and calcareous soils are ideal for growing wine grapes for several reasons. First, calcareous soils are porous but also retain water well, allowing vines to flourish in both very wet years and during droughts. Second, these soils are alkaline. A pH greater than 7.0 fosters better absorption of nutrients because hydrogen ions are displaced by calcium, potassium, sodium, and magnesium. Calcium is especially important in helping keep the pH of grape skins relatively low. A consistently low pH (higher acidity) is attractive to winemakers because it contributes to the longevity of bottled wine. 

When making decisions about harvest timing or blending, we evaluate acidity as a key component – just as winemakers in Bordeaux have done for more than a century. Paso Robles and Bordeaux share similarly limestone-rich soils and a reputation for producing remarkable wines with great propensity for aging gracefully.

At JUSTIN, we’ve been working with Bordeaux-style varieties like cabernet sauvignon, cabernet franc, and merlot for more than 40 years. We’re fortunate that the fruits of our labor continue to garner praise from both consumers and critics alike.