The search for the sweetest cherry tree is a quest for the cultivar that consistently achieves the highest concentration of sugar, which scientists and growers measure using the Brix scale. This scale measures the percentage of sucrose by mass in a solution; a 20 Brix reading means the fruit is approximately 20% sugar by weight. While individual taste involves a balance of sugar and acid, the designation of “sweetest” scientifically belongs to the fruit with the highest measured sugar content.
Distinguishing Sweet and Tart Cherry Varieties
Cherries are broadly divided into two main groups based on their species and taste profile, which significantly impacts their use. The sweet cherry belongs to the species Prunus avium, and these trees produce the large, firm, and juicy fruit primarily marketed for fresh consumption. Sweet cherries naturally contain a high sugar content alongside a relatively low acid level, giving them their characteristic flavor.
The second group is the sour or tart cherry, Prunus cerasus, which is a smaller tree and yields fruit with a distinctly different chemical composition. Tart cherries, like the popular Montmorency variety, have a much higher acid content that overshadows their sugar, making them tangy rather than sweet. These varieties are typically reserved for processing, such as baking into pies, making preserves, or juicing, where their acidity provides a necessary balance to added sugar.
The Cultivars Known for Peak Sweetness
The cherry variety most frequently cited for achieving the highest Brix levels is the ‘Rainier’ cherry, a cultivar developed in 1952 at Washington State University. A hybrid of the ‘Bing’ and ‘Van’ cherries, ‘Rainier’ is known for its golden-yellow skin with a distinctive red blush and exceptionally creamy white flesh. Brix measurements for ‘Rainier’ cherries consistently range from 20 to 25, which is higher than many other commercially grown sweet cherries.
Another contender for peak sweetness is the ‘Skylar Rae’ cherry, a variety that can reportedly reach Brix levels as high as 32 under ideal conditions. This newer variety, similar to ‘Rainier’, maintains an extremely high sugar content with very low acidity. While the classic dark-red ‘Bing’ cherry is a standard for sweetness, typically measuring around 17 Brix, other modern cultivars like ‘Sweetheart’ and ‘Skeena’ are also bred for high sugar content. ‘Sweetheart’, for instance, is a late-ripening, self-fertile variety that can achieve Brix levels in the 20 to 22 range.
Varieties like ‘Rainier’ and ‘Skylar Rae’ taste intensely sweet partly because they have a low acid profile, which allows the high sugar content to dominate the flavor experience. This is in contrast to some darker cherries, which may have a slightly lower Brix but a higher acid content, giving them a richer, more complex flavor profile.
Environmental Conditions That Boost Sugar Content
A cultivar’s sweetness potential is only fully realized under specific environmental conditions and horticultural practices. Sunlight is a primary driver, as the process of photosynthesis converts solar energy into sugars, which are then transported and stored in the fruit. Cherry trees require full sun exposure, typically six to eight hours per day, to ensure maximum sugar production and fruit quality.
Controlled water stress, also known as deficit irrigation, is a technique growers use to concentrate sugars in the fruit during the final ripening phase. Providing slightly less water than the tree needs at this specific time limits fruit swelling, which prevents the dilution of sugars and organic acids, resulting in a higher final Brix reading. Conversely, too much water late in the season can cause the fruit to rapidly swell, diluting the sugar content and potentially causing the cherries to crack.
Nutrient management in the soil also influences sweetness, with potassium playing a significant role in the plant’s metabolic processes. Adequate potassium levels support the transport of sugars from the leaves into the developing fruit, contributing to higher soluble solids content. Harvest timing is crucial, since cherries are a non-climacteric fruit and will not ripen or increase in sugar after being picked. Allowing the fruit to remain on the tree until it reaches peak ripeness is necessary to achieve the highest possible sugar accumulation.