In the early years of the Meiji period from 1868 to 1912, powdery mildew and downy mildew infected rootstocks grown abroad were unwittingly brought into Japan, and it was just a matter of time before the mildew spread to Yamanashi Prefecture. As a result, grapevines weakened and grape growing became difficult. When “Bordeaux Mixture”, a pesticide developed in France to combat the mildew and protect grapevines, was successfully introduced to remedy the situation, this shrine was built in honour of the pesticide. The inscription on the stone pillar at the shrine reads: “Master Saburo Matsumoto (the son-in-law of Kotaro Miyazaki) built this.”

As we proceed to Iwaimura Vineyard, you will see the wine gallery where we will taste 6 different varieties of wine at the end of our tour.

Overhead, you will see pergola-trellis-trained Koshu grapes used for our white wines. As we continue walking to the Iwaimura Vineyard, you will hear the creek that once powered the winery’s water wheel. Ahead is an immature French oak tree. The trees used to make barrels in France are at least 200 years old, so this one isn’t in danger of becoming a barrel any time soon. Beside the oak tree is the vineyard. There are about 20 different varieties of grapes growing in this vineyard. Each row has 2 or 3 different varieties. Pinot Noir is the first to ripen and Cabernet Sauvignon is the last. October is the best time to see the vineyard in all its glory. Generally speaking, 1 kg of grapes is necessary to produce 1 bottle of wine. If you look closely at the vines, you will see several examples of vertical shoot positioning (VSP): Guyot, Double Guyot, Cordon and Double Cordon.

Kotaro Miyazaki, our predecessor who successfully established a winery on this land, was born here. There is a museum dedicated to Miyazaki and his winery located on the second floor, and the adjacent building was once a winery. The original house was a traditional structure with the second floor reserved for sericulture, the raising of silkworms for silk production. The second floor was later raised by an extra 2 meters to assume its current Western appearance.

The smell of oak-aged wine is absolutely Devine! It’s a heady mixture of evaporating wine from the 500 to 600 barrels stored here. Château Mercian ages 90% of its wines in French oak, which is generally accepted as being the best as it is highly aromatic. These complex aromas result from the fact that the most sought after oak only grows in a few regions of France, where the soil is poor in nutrients, not too moist, and contains no iron. The oak’s fine porosity is a result of it growing extremely slowly in the ‘poor’ soil. The winery also uses American oak for about 10% of its wines. American oak is also very aromatic and has proven to be well adapted to maturing red wines with an intense palate. Its sweet coconut aroma goes very well with our Muscat Bailey A red wines and some of our Chardonnays.

These barrels can be used for up to 10 years. The first 2 years of use results in the very best wines. Each year we add about 100 new barrels and we keep a total of about 1000 of these barrels all together. White wines are oak-aged up to 6 months, while the reds age anywhere from 15 months to as long as 30. The ideal temperature of this cellar is 19 degrees Celsius, so it is necessary to run a cooling system in the summer months. In addition, we keep the humidity at around 70%. Anything less than 70% humidity will cause the wine to evaporate too quickly. If you look closely at the lids of the barrels, some have MT or MTL+ (Medium Toast/Medium Toast Long +) indicated on them. Toasting the insides of the barrels gives a vanilla, chocolate, roasted almond or caramel aroma to the wines. In fact, we can order 7 different levels of toasting from the manufacturers to suit our exacting specifications. There are also lids made from cherry and acacia! These lids give a slightly different aroma and flavor to our wines.

These ten French oak casks of around 3300 litres each were ordered in the late 2010s. The smaller barrels we keep in our underground cellar have a much greater impact on wines as the surface area of the barrel is in contact with a much smaller volume of liquid. Such large casks as these, which hold 15 times more wine than regular-sized barrels, have a softer impact on wines and can be used for up to 30 years! That’s 20 years longer than our regular-sized barrels. We make our Aiakane Merlot/Muscat Bailey A blend, our Moegi Chardonnay/Koshu blend and other blends from the wines aged in these casks. It is interesting to note that the concave ends of these casks offset the pressure from the large volume of wine pushing outward. These casks have two large valves. The one on the front of the cask is for transferring wine, while the one at the bottom is for clearing out the sediment. The sediment is eventually spread on our vineyards.

We ask that you stay within the demarcated area for your safety. This large building houses a variety of tanks from large 20,000 litre tanks to 2000 liter French oak vats. We use some of these tanks in order to make single vineyard wines with distinct terroir. The various tanks in this room provide us with the flexibility to get creative with our wines.

We are now entering our outdoor grape reception area with a platform from which to view the process of destemming and crushing of grapes. This area is very busy during the harvest season from the beginning of September through to the end of October. From November to August, we present a short 2 to 3 minute video of what happens here during the harvest season.

Although we process around 550 metric tons of grapes here at Château Mercian, Katsunuma Winery, not all the grapes come from Katsunuma. Some of the grapes are actually grown in other prefectures such as nearby Nagano.

More than 10 varieties of grapes are processed at this facility. Cabernet Sauvignon grapes are the last to be processed in late October, while Bailey Alicante A, Sauvignon Blanc, and Chardonnay grapes are among the first to be processed from the end of August to the beginning of September.

On the far left you will see red wine fermentation tanks. In order to circulate the grape skins that tend to float to the top of the tanks, the tanks are rotated 4 turns to the right and then 3 turns to the left at least once a day. In addition, in order to introduce oxygen to the fermenting red wine, about half the liquid is pumped out into a large tank and then pumped back in at the top each day. The process of fermenting the red wine takes from 7 to 10 days.

Next, directly in front, you will see large bags suspended from the ceiling which deliver nitrogen gas to help reduce oxidation when crushing and pressing grapes for white wine. Red wine benefits from the introduction of oxygen during the fermentation process, white does not.

The large machine in the middle (Bucher Vaslin) is a grape crusher and destemmer that can handle 10 metric tons! We also use smaller 5 ton, 3 ton and 1 ton machines.

Cellar B

Château Mercian processes a total of around 700 metric tons of grapes each year, around 550 tons of which is processed at this facility. The harvest begins in early September and finishes by late October.

The larger French tanks in this room are for red or white wines and are around 15,000 litres in volume. The French tanks show a distinct inclined weld for ensuring all remaining sediment can be removed after fermentation. The smaller Japanese tanks in this room are strictly for white and rosé wines and are around 6,000 to 10,000 litres in volume. Cooling jackets surround both types of tank. The fermentation temperature for white wines at this winery is from 18 to 22 degrees Celsius, while the fermentation temperature for red wines is around 30 degrees Celsius. You can see a large cooling system in this room that supplies 4 to 5 degree Celsius water to these cooling jackets.

Although many of these large stainless steel tanks look identical in size, their actual volumes vary considerably, so the Japanese tax authorities have had the winery develop painstaking methods for measuring volume. Thus, a newly acquired tank, whether produced overseas or domestically, is filled with a known quantity of water and then the water level inside the tank is checked with a measuring rod reserved specifically for that tank in order to accurately determine its total volume. By doing so, the winery can quickly and accurately determine the amount of tax it must pay to the Japanese tax authorities.

This tour of Château Mercian, Katsunuma Winery, will last for approximately 90 minutes. Before we tour our facilities and taste 6 different varieties of our wine at the wine gallery, please join us for a short video presentation about Château Mercian. Please have a seat while you view the 8-minute video presentation about our wineries, our history and how we make our red, white and rosé wines. Later, we will walk to the areas where we process, ferment and age our wines.

In this cellar dating from the early twentieth century, you can see 19 French oak barrels, each with a specially assigned number and its accurate maximum volume rating. Although large oak barrels and stainless steel tanks often look identical in size, their actual volumes vary considerably, so the Japanese tax authorities had the winery develop painstaking methods for measuring volume. Thus, a newly acquired barrel, whether produced overseas or domestically, is filled with a known quantity of water and then the water level inside the tank is checked with a measuring rod reserved specifically for that tank or barrel in order to accurately determine its total volume. By doing so, the winery can quickly and accurately determine the amount of tax it must pay to the Japanese tax authorities. From 1975 to the year 2000, large numbers of sommeliers from around Japan were invited to try wine straight from these barrels! Of course the amount the sommeliers consumed was reported to the tax authorities. It is interesting to note that the beam at the entrance to this cellar had to be shaved down in order to get these large barrels into the cellar. Some of these barrels were in use as recently as 2010.