My first thought is to let them stay on the bush longer,a week or more,after they get as blue as possible.Do they have at least six hours of sunlight? Brady

Soil acidity won't directly affect taste. Perhaps could indirectly by affecting leaf area and leaf to fruit ratio. So I don't think that is the issue.

Jewel is tart unless fully ripe. So follow Brady's advice and try leaving them on the bush longer. I sometimes leave mine weeks after turning blue. But with some varieties in hot weather that can cause the berries to go too soft.

Some of the large blueberries we buy from store do not taste tart at all, just a little sweet. But the taste is so plain. I do not know if they are from greenhouse, or from hydroponics.

I grow more than 10 varieties of blueberry, but I do not see a lot of difference in terms of the tastes. They taste similarly to the U-pick berries.

The taste has more to do with cultivar, sunlight, fertilizer and irrigation.

I grow blueberries but have never noticed if water makes a diffrence. I do know some years they seem a lot sweeter. I know leaving them on longer always works to a point.

@Bradybb, yes they get at least 6 hours of sunlight now in the summer. I live in Brazil and we get a lot of sunny days.
But a few months ago I put artificial fertilizer on the bushes and some of the leaves got burned, so maybe the soil got too acidic to the point of interfering with the taste?

This post was edited by julia.scheidt on Thu, Jan 1, 15 at 15:19

so maybe the soil got too acidic to the point of interfering with the taste?

No blueberries being too acidic is like too much sun for coconuts. It's almost impossible to be too acidic. No, has nothing to do with it, leave them on the bush longer, they are not ripe.

Soil ,weather, and water can affect the taste of fruit. Many of us know this from growing apples etc. and having a wide variety of opinions of taste of a variety. Sour blueberries are typically attributed to not being ripe but I would say that is not always true. You may want to read up on a few examples of things being affected by soil/water combinations http://www.npr.org/blogs/thesalt/2012/06/01/154072388/how-to-grow-the-tastiest-tomato-the-secret-s-in-the-soil

http://www.winegeeks.com/articles/139

http://www.ediblegeography.com/sweet-and-sour-soils/

www.njfarmfresh.rutgers.edu/documents/CanSoilFertilityImproveTomatoFlavor.pdf

It is possible the excess fertilizer hurt the plant, and I would agree crops can vary but of all fruit blueberries are almost as steady as raspberries. Taste varies little. Plus when you burn plants with fertilizer, it's not that the fertilizer is acidic, it's too much nitrogen. It's not an acidic burn. We know blueberries love to be acidic and will not produce or grow if not extremely acidic. A big difference between too much acid and too much nitrogen.
Leave berries on longer, and also you may get a better tasting crop as plant matures. The idea that the acid from the soil is responsible for the acid in the fruit though is just not true.
I have found that some blueberry cultivars are always sweet and other need to be blue for weeks before they are sweet. They do vary a lot. I also have observed that these tart berries are the better berries when they finally sweeten up too.