V.A.
Get to know Slovenian wine - Posavje region, Bizeljsko-Sremič wine district
In this post, I am presenting You, the Bizeljsko-Sremič wine district, which is a part of the Posavje wine region.

The name Bizeljsko-Sremič comes after the two most famous wine villages. The district is known mostly on the local market.
Fun fact: In this region is the town called Sevnica, where the former first lady of the US comes from.

Climate:
Vineyards are found on the hills between the altitudes of 200-400m, with their slopes facing in all directions. The climate is continental with cool winters and warm to hot summers. With high levels of rainfall.
Soil:
At least three different soil types can be found over each bedrock. The soils are heterogonous, and they are often changing. Still, the primary soils are sandy with clay, mostly on marl and limestone. Examples of quartz sand are also found.
What grows there:
The white varieties of the region are similar to those in Štajerska Slovenia. The most commonly grown varieties are Welschriesling, Sauvignon Blanc, Chardonnay, Riesling, Muscat Blanc à Petits Grains, and Pinot Blanc.
White Bizeljčan PTP is a white blend on entry-level, made from Welschriesling (30-60%), around 50% of Sauvignon Blanc, Pinot Blanc, and Chardonnay; up to 20% of Rumeni Plavec and around 10% of any other white variety.
Red Bizeljčan PTP is a red blend on entry-level, made from Žametovka (40-60%) and Blaufränkisch (10-33%), between 5 and 15% of other red varieties are allowed, also up to 25% of white varieties are allowed to be used in the blend.
Rumeni plavec is a specialty of the district. It is a high-yielding indigenous white grape with low sugar and high acidity. Mostly used for regional blends and very few examples as a varietal wine. Istnič winery is using it as an addition to sparkling wines, which gives the wines a local character and distinction.
Worth mentioning:
Istenič winery from the village of Stara vas. The names behind the winery are Janez Istenič and Miha Istenič (father and son). The Istenič winery is a pioneer in sparkling wine production in Slovenia. They were the first ones to introduce the »special cuvées«, which are a line of premium sparkling wines aged 36-60 months on the lees.
For the production of sparkling wines, they are using the traditional method. The wines are based on Chardonnay and Pinot Noir, with a notable part of Rumeni Plavec in some of the Cuvées (adds acidity).
The KZ Krško Agricultural Cooperative is the largest producer of Cviček in the country. Most of the grapes are grown in the Dolenjska district. The top 15% of their premium wines are made from grapes grown on the left bank of the Sava River, from the Sremič. The sweet wines they produce are exceptional. They also show a prospect in the production of the Blaufränkish.
Repnice – are underground pits manually dug into the million years old quartz sand. They can keep their initial shape forever. In the past, those pits were used for storing crops. Repnice can maintain a constant temperature of 8'C and moisture levels of 95%. Due to the high humidity levels, they are not appropriate for wooden barrels. Therefore they were used as wine-cellars when the stainless steel vessels came into use. Sometimes repnice were also used for storing wine, which was not labeled, of course. Nowadays, most of them are abandoned. A very few are in use as tasting rooms, and some serve as a tourist attraction.
Bizeljsko-Sremič in a nutshell:

Source: Slovenia Winemaking country, by Robert Gorjak. Page 102-108.