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  • Writer's pictureApu Winery

Diurnal Temperature Variation at Our High-Altitude Winery

Updated: May 22, 2021

Vineyards in Eastern Washington State and Mendoza, Argentina are renowned for their diurnal temperature variation, AKA thermal amplitude. Thermal amplitude can be described as an extreme temperature range within a 24-hour period (hot days and cool nights). Here at our high-altitude vineyards in the Peruvian Andes, we have considerable temperature shifts. Due to our high elevation, days are hot and nights are cold. However, it never freezes here because our proximity to the Amazon Rainforest. To give you an idea of these shifts in temperature, here is a recent snapshot of our thermometer:

The low of the day was 3.5°C (38°F) but the high was 35°C (95°F), giving us a thermal amplitude of almost 32 degrees Celsius

So how does a drastic thermal amplitude affect the plants and influence our wine? The answer comes down to photosynthesis, respiration and the energy saving abilities of vines. During the day, plants undergo photosynthesis to produce energy and store carbohydrates (glucose). Plants also respire, which is when they convert nutrients obtained from soil into energy for their cellular activities.

At night, plants continue respiration, but can't photosynthesize without sunlight. This means the vines use less energy at night. Also, respiration slows with colder temperatures, so the lower the nightly temperature, the less energy the grapevine consumes. Plants can therefore use this leftover energy for their fruit, creating berries that are more rich, colorful and intense. Moreover, the heat during the day allows our grapes to ripen faster and develop more sugar, while also developing darker fruit flavors and thicker skins, giving us some lovely tannins in our wine. Finally, as we have mentioned in previous blog posts, cool nights are also crucial for generating acidity in the grapes.

It was quite surprising for us to find the optimum viticultural conditions at this location in the Peruvian Andes. Thanks to our proximity to the jungle and our high-altitude, an exceptional thermal amplitude works in our favor 365 days of the year, providing us a premium wine that is fruity, balanced, colorful and robust.


“Visiting Mendoza, Argentina Part 1: A Question of Altitude.” Wine Anorak, 2008,


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