Japan Blueberries
Japan Blueberries photo copyright 2015 AppleWasabi


During late August, as warm nights turn cool, one of the great fruits of summer offers forth its bounty.  Blue food is a relative rarity in nature and this perhaps adds a special cache to the blueberry.  In North America and Northern Europe berry picking is a rite of summer.  With schools on summer hiatus, young mothers corral their children to the the outskirts of towns and villages to pick ripening berries from June to August.  It is often a fond memory of summer childhoods, picking delicious berries – a few for the picking basket and a lot for the mouth!

In Japan blueberries grow very well in climates akin to the lands of their natural origins.  Nagano is one such place and as we packed our kit for a week of picking old memories of Canadian summers flickered in the mind.  The Japanesebelieve that highbush blueberries taste better than other types of blueberries.  Today they are very popular especially amongst elderly because of the healthy dose of propanol they provide in addition to their delicious taste.

Karuizawa is the place Tokyoites head to for summer vacation.  It is in many ways the opposite of the concrete modernity found in the world’s largest metropolitan.  In place of tall buildings and designer malls are old-growth trees towering over green moss carpets.  The draw here is clearly the cooler climate and natural serenity.  On a non-picking day we scaled the —- mountain where one could step left and be in Nagano or right and be in Gifu.

Nagano Mountain
Nagano Mountain photo copyright 2015 AppleWasabi



The first introduction of blueberry plants to Japan was in 1951.  Commercial blueberry culture was slow to take root until after 1980 when demand for blueberries took off.  Planting of blueberries grew from 10 ha to about 400 ha during that period.  Domestic supply is vastly outstripped by  demand with around 13,000 t of fresh and frozen fruit imported.  Japanese consumers have a preference for fresh over other forms of blueberry fruit.  Large and sweet blueberries are the preferred choice with a significant part of consumption for health benefits.

Within Japan blueberry growing regions may be roughly divided into three zones. Northern highbush are grown in Hokkaido, the northern regions of Honshu (mainland) and the highland areas of central Honshu that are relatively cool during the growing season (April to October).  One of the great challenges in producibng high quality fruit is the ripening season lands during the rainy season of early summer.  Soil types evolved from volcanic ash and tend to have poor aeratability and drainage.

Blueberry research in Japan focuses on breeding early-ripening cultivars with bigger berries and sweeter fruit. Two examples are the Utsuboshi and Amatsububosh.  The blueberry growing area is projected to expand to 1,000 ha with production volume increasing to over  3,000 tonnes.  Now that Japanese have a taste for blueberries the future for blueberry production in Japan is bright.

Nagano Mushroom
Nagano Mushroom photo copyright 2015 AppleWasabi


Plan to make a day of picking blueberries as it will take a minimum of 3 hours to accumulate an amount adequate to share with your family and friends.  If you plan on making jam or freezing the berries whole then consider doubling the amount of time spent picking to 6 hours.  It may seem like a lot of time but you will thank yourself many times over throughout the year.  How much one can pick comes down to your own efficiency together with how high the bushes are and how big the clusters of berries grow.  Wild blueberries will yield the fewest for your time spent whereas high bushes – that allow you to stand while picking – will yield the most.

Fresh Blueberry
Fresh Blueberry photo copyright 2015 AppleWasabi


Research by the United States Dept. of Agriculture suggests that blueberries may contribute to reversing the aging process.  Additionally, memory has been shown to improve while motor skills deteriorate more slowly with age.   The possibility that the loss of short term memory as we age can be reversed may also be attributed to blueberry consumption.  What makes blueberries so special?  They are packed with more antioxidants than any other fresh fruit or vegetables which makes them nature’s number one source.

Blueberries are also one of the highest sources of saliicylate. It acts like a natural aspirin and has been shown to reduce inflammation and prevent blood coagulation.  In Japan blueberries are the rockstar of healthy fruit with informercials proclaiming their health improving virtues and anti-ageing properties.

Recent research has found that the European type of blueberry can improve night vision.  n Japan blueberries are now known as the “vision fruit” for their healthy contribution to better eyesight.   Finally, Anthocyanins and proanthocyanins found inside blueberries may contribute to stabilizing the collagen matrix in bones thereby reducing oncoming osteoporosis.  All told, blueberries pack a lot of nutritional value that – combined with their wonderful taste – make it a compelling fruit to add to a healthy diet.

Summer Blueberry
Summer Blueberry photo copyright 2015 AppleWasabi


Blueberry season begins in early July and runs until late August in Japan whereas if you live in North America and Europe you will need to wait until August.  Fruits are ready for harvesting once their skin turns blue and their flesh become soft to the touch.  The fruits should be carefully picked to avoid bruising.  When shopping at a store look for blueberries featuring a dark blue skin color with a mottled white haze and a fragrant aroma.  Don’t be afraid to smell it as this is one of the most reliable ways to gauge a fruit’s ripeness.  They should be devoid of any wrinkles, cuts and patches on the skin.  Berries with spots and bruises will spoil quickly.

Nagano Mountains
Nagano Mountains photo copyright 2015 AppleWasabi


Blueberries can be  placed inside the refrigerator but should be stored in a breathable container such as cardboard.  Keep covered loosely with plastic to preserve the moisture content and preferably store in a humidity controlled environment.  Ideally, blueberries should be eaten within a week after picking however they are at their best the day they are picked so consider preserving or freezing them the first day.

Japan Blueberries
Japan Blueberries photo copyright 2015 AppleWasabi


Eating blueberries is very simple as they contain no seed.  Remove stems and leaves, rinse with cold water and towel dry.  They are ready to go!  If you are freezing them then make sure they are completely dry and freeze on large trays.  Once frozen transfer to sealed plastic bags or containers to preserve their aroma.  This method allows for easy separation of the berries when you retrieve them from the freezer at a later date.

 Picking Blueberry
Picking Blueberry photo copyright 2015 AppleWasabi


The delicate nature of summer blueberry makes it require special care when cooking it.  On high heat the berries will explode and lose their beautiful form so unless you are making a sauce avoid extreme heat.  A better approach is to add the sugar in the recipe and mix with the berries carefully.  Leave them covered in a non-reactive container (ceramic or glass) overnight at room temperature.  The next day the sugar will have drawn out the water from the berries without damaging their shape.  Strain the liquid from the berries and proceed with the recipe cooking just the liquid first.  Only at the end – and for a very short time – do you add back in the whole fruit.  This has the benefit of preserving the berry shape and creating two layers of flavor – one cooked a short time and the other for a long time.

Japan Blueberry
Japan Blueberry photo copyright 2015 AppleWasabi


This recipe follow the advice mentioned above and is a technique rooted deep in European traditions of preserving.  In France this method is called “CONFIT” and can be found being practiced today in northern Alsace as well as Provence in the south.  It is the ultimate method for preserving and has the added benefit of dividing a big job into smaller parts to be carried out over multiple days.  It definitely makes the process more enjoyable and takes full advantage of natural forces to “ease the workload”.

For those looking to cut sugar from their diet – consider halving the sugar with the caveat that the jam must be either refrigerated or frozen at all times.

  • 1000 g Blueberries
  • 825 g Sugar
  • 40 g Lemon Juice ( 1 whole)
  • 1 Vanilla Bean sliced in 1/2 and beans scraped
  • zest of 1 lemon
Day 1 –  Fruit Maceration
  1. Rinse the Blueberries in cold water.  Dry and de-stem them.
  2. In a ceramic bowl gently mix the whole Blueberries with the lemon juice, zest, vanilla and sugar.  Fit a sheet of parchment paper tightly over the top surface of the berries and refrigerate overnight.
Day 2 – Gentle Heat
  1. Remove the bowl from the refrigerator and place the contents in a wide saucepan.  Gently simmer over low heat until warmed through.
  2.  Pour the contents back into the ceramic bowl, cover with parchment and return to the refrigerator overnight.
Day 3 – Finishing Jam
  1. Strain the bowl contents through a sieve in order to separate the fruit from the liquid.
  2. In a wide mouth saucepan bring the syrup to a boil.  Skim off impurities and continue to boil until it reaches 105 Celsius on a candy thermometer.
  3. While the syrup is boiling puree 1/3 of the berries in food processor or use a hand blender.  Keep the remaining 2/3 whole.
  4. Add the berry puree and whole fruit to the saucepan and return to a boil for about 5 minutes.  Once the strawberries become translucent check the set on a cool ceramic plate or stone countertop.
  5. Pour the hot jam into sterilised jars and seal for 10 minutes in either a 100 Celsius oven or boiling water.
  6. Cool Jars upside down for 48 hours.
  7. Store in a dark cool place like a fruit cellar or wine cellar for up to 1 year.