Alsace Part 2: The Geology - The Vosges Mountain Paleozoic Evolution

Who knew that learning about the geology of the Alsace would be so complicated. I've already written three blogposts about it!
My first blogpost, Alsace Part 2: The Geology - The Layout of the Land was to give a general overview of the geology of the Alsace. Then I began getting into the weeds with Alsace Part 2: The Geology - The Location of the Upper Rhine Graben, in order to give a context to the next blogpost, Alsace Part 2: The Geology - The Vosges and the Black Forest Mountain.
My focus today will be on the Vosges Mountains. I am interested in learning about the geology of the Vosges Mountains because it is in this location, the sub-Vosgian Hills that the Alsatian vineyards have found a home.
To understand how the different soil types were formed, we have to go way back to the Paleozoic times, some 380 million years ago in the Middle Devonian Period to the late Lower Carboniferous Period (330–320 Ma).
Traditionally, the Vosges Mountains were divided into two parts, the northern Vosges of Saxothuringian affinity and the southern Vosges correlated with the Moldanubian domain.
Skrzypek divided the Vosges Mountains into three parts, based on the underlying rock strata (lithostratigraphy).¹

I found the reference by Etienne Skrzypek to be the most helpful in understanding the Paleozoic origins of the Vosges Mountains. Looking at the illustrations contained in the reference summarized the extensive and detailed information contained in the 36 page book chapter.
In the illustration below, I've labeled the major features.¹

The above illustration and the cross section below, which begins from the Northern Vosges Bruche unit and ends at the southern end of the Vosges Mountains, tells the story of the various rock types contained therein.¹

The authors used lithological, structural, petrological and geochronological data to recreate the sedimentation, magmatism, metamorphism, and deformation forces that comprised the geodynamic history of the Vosges Mountains.
I think a picture is worth a thousand words so with those two illustrations above, I will end the blogpost, but hope to synthesize this information with a final blogpost on the geology of the Alsace and it's relevance to the Grand Cru vineyards of today.
References:
1. Etienne Skrzypek, Karel Schulmann, Anne-Sophie Tabaud and Jean-Bernard Edel, (Palaeozoic evolution of the Variscan Vosges Mountains) in K., Martınez Catalan, J. R., Lardeaux, J. M., Janousek,V.&Oggiano, G. (eds) The Variscan Orogeny: Extent, Timescale and the Formation of the European Crust, Geological Society, London, Special Publications, 405, http://dx.doi.org/10.1144/SP405.8, The Geological Society of London 2014.

Vintage 2020: Still Winter But a Nice Warm One

Okay, I'm going to jinx it but we have been having a very mild winter so far. This has allowed us to work in the vineyard to get a jump start on the pruning we have to do. Our first task, learning from last year is to free the vines from the trellis wires by cutting off all of the tendrils that have wound its way on the wires.
Today, the temperatures reached a balmy 50 degrees and our friends came to lend us a hand. It was great that our friends came because she is a trained veterinarian and we had a skeleton for her to identify. The head was the most prominent feature that was left and there was a bit of fur so the identification was difficult to say the least. She did think that it was a young whatever because of the bone and teeth remains.

That was the excitement in the morning. Since our friends came to help us, we were able to go home for lunch and come back to do a second shift! This is the earliest in the year that we were able to do a double shift. We are trying to get ourselves fit for the season to come.

2017 Domaine Guiberteau Samur

Along with our interest in Alsatian wines, we are still on our quest to understand the various flavors of Cabernet Franc grown in different regions of the world. My husband picked up this 2017 Domaine Guiberteau Samur, recently and we had it one evening with dinner.
We have had the 2013 Domaine Guiberteau Samur White Wine and the 2014 Domaine Guiberteau Les Moulins White Wine, both made from Chenin Blanc grapes, when we were on our "learning about Loire Chenin Blanc" quest, but this was our first foray into Domaine Guiberteau's red wine.
The wine was nicely extracted and was very dark purple in the glass. The taste was a nice balance of fruit and acidity and very drinkable now.

2016 Agathe Bursin Parad' Aux Pinot Blanc

While learning about the Alsace, we have also been tasting wines from the region. This is the second bottle of Agathe Bursin that we are trying. The first was that I blogged about was the 2016 Agathe Bursin Strangenburg Pinot Noir. This is a wine made with a blend of Pinot Blanc and Auxerrois. We are totally familiar with Auxerrois because that is one of the varieties of white grapes that we grow. We feel that we get stone fruit flavors from our Auxerrois, which can taste of white peach and nectarines.
We had the 2016 Agathe Bursin Parad' Aux Pinot Blanc wine over several nights. On the first night, I believed that the wine might have been fermented in oak barrels because I thought I tasted the influence of oak on the wine. On the second night, it still retained some of the oak influence, for me, but on the third night (I know, you ask, how does one bottle of wine last for 3 nights!), we had this wine with a salad topped with butter basted pears and blue cheese. The magic was there! Here is a wine that pairs deliciously with blue cheese!

Valentine's Dinner at La Finesse

A long time ago, pre-kids for our friends, we used to get together with them and take turns making Valentine's Dinner at our homes. We would go to extreme lengths to make the meal and in one iteration our friends called their abode, La Finesse. In a nod to them, since they and their two teenage children are on their way to Ecuador, we decided to invite our vineyard migrant-worker friends, for a La Finesse redux.
So, the invitations were sent out by email on Feburary 10 and all that remained was to determine what the menu would be. Yikes! Then, my husband was on the Wine Beserker's Epicurean Exploits forum and found a beautiful recipe, just in time to quell the rising fear of culinary indecision. When he showed me the beautiful photo of the port infused short ribs, the menu came together!

We began our dinner with a few appetizers, smoked salmon, soppressata, a soft and a hard cheese, and a crudite platter and paired it with a bottle of Egly-Ouriet. The back of the label said that the disgorgement date was in 2006. We normally are in love with this champagne, but when we opened this bottle, the color was dark yellow and we were a little concerned that it was oxidized. The fact that it poured out with little to no bubbles confirmed our fears. It drank more like a still wine.
After lingering over our appetizers, my husband served up his port infused beef short ribs which topped a stack of sauteed Swiss chard and spinach, layered with mashed potatoes and covered with the braising liquid sauce.

We paired our entreé with a 1993 Ridge Monte Bello. It was a beautiful marriage of beef and Cabernet Sauvignon!

Our friends contributed to the menu, bringing a chocolate mousse as well as a beautiful and delicious apple tart tatin for dessert.

All in all, we had a wonderful time, great company and in a relaxing atmosphere. I think La Finesse had a rebirth.
How to make the Port Infused Beef Shortribs:Cooking preparations began at 11 a.m. on Friday morning with my husband doing all the preparations. He prepared the mirepoix, a mixture of chopped celery, carrots and onions which he sauteed in a pan. In another pan, he browned the beef in duck fat, then removed the browned beef. To this pan, he put one bottle of red wine and two bottles of port and brought it to the boil, scraping up the browned beef bits into the liquid. He added a head of garlic with the top cut, along with fresh thyme to this liquid. He put the meat into a disposable aluminum pan and covered it with the wine/port liquid and braised the meat in the oven set at 325 degrees for 1-1/2 hours. The beef that is exposed to the oven temperature will get a brown crust. Turn it over into the liquid and cook for another 1-1/2 hours, 3 hours total, or when the meat begins to fall off the bone. Use the liquid and make a sauce, separating the mirepoix and the fat. While the beef is almost done cooking, wilt the Swiss chard and fresh spinach in chopped garlic and set aside. Make mashed potatoes and set aside. To serve, place Swiss chard/spinach on the bottom, top with mashed potatoes and top with beef short rib. Pour sauce over the tower of treats!

Alsace Part 2: The Geology - The Vosges and the Black Forest Mountain

In my previous post Alsace Part 2: The Geology - The Location of the Upper Rhine Graben, I gave a 35,000 foot view of the location of the Upper Rhine Graben and it's context in the European continent. The Upper Rhine Graben (URG) is an important geological feature in the Alsatian Wine growing region. The topological map of the Upper Rhine Graben and the location of major cities is shown in the illustration below:

On the left side of the above illustration, the topographical map shows that the highest features, the Vosges Mountains on the west and the Black Forest Mountains on the east, occur in the southern Upper Rhine Graben. The map also shows that as one goes farther north, the terrain becomes lower in elevation.
My focus will be on the southern URG because most of the Alsatian vineyards are located on the eastern slopes of the Vosges Mountains, in the region known as the sub-Vosgian Hills that stretches from Mulhouse in the south to Strasbourg in the north.

The illustration that was shown in Alsace Part 2: The Geology - The Location of the Upper Rhine Graben as well as the above two illustrations serves to set the stage for understanding where the various soil types that exist in the Alsace came from.
Also helpful to me was the time line⁴ shown below so that I could put events that were happening in the Alsace into geological context.

Some of the oldest rocks in the southern URG, known as the basement rocks are exposed on the flanks of the graben, mostly in the Black Forest and the Vosges Mountains. They include a variety of intrusive, metamorphic and Cambrian to Visean sedimentary and volcanic rocks of the Variscan Internides.³ (The Variscan Internides are built up either from the so-called Armorican Terrane Assemblage, that is peri-Gondwana crust initially situated south of the Rheic Ocean, or rock complexes that formed along the active margin of the Rheic Suture Zone.⁵)

A geological conundrum in the URG is that although some of the oldest rocks are known to exist in the Vosges and the Black Forest Mountains, the exposure of these rocks, or the uplift of the Vosges and Black Forest Mountains is generally thought to have occurred during the Miocene, or even during the Upper Pliocene 􏰀Pleistocene, quite late in the history of the URG.³
Having set this stage of the ancient geological history of the Vosges and Black Mountains, what is next is to explore the soil types that were being formed during the intervening years of the Variscan Orogeny and the uplift of the Vosges and Black Mountains that resulted in the soils that are so conducive to wine growing in the Alsace. Stay tuned.
References:
1. Li, Y., Tsukamoto, S., Frechen, M. & Gabriel, G. 2018 (January): Timing of fluvial sedimentation in the Upper Rhine Graben since the Middle Pleistocene: constraints from quartz and feldspar luminescence dating. Boreas, Vol. 47, pp. 256–270. https://doi.org/10.1111/bor.12266. ISSN 0300-9483.
2. Markus E. Schumacher, Upper Rhine Graben: Role of preexisting structures during rift evolution, TECTONICS, VOL. 21, NO. 1, 1006, 10.1029/2001TC900022, 2002.
3. Yair Rotstein, Marc Schaming, Tectonic implications of faulting styles along a rift margin: The boundary between the Rhine Graben and the Vosges Mountains, Tectonics, 04 March 2008, https://doi.org/10.1029/2007TC002149.
4. The Geological Society of America, GSA Geologic Time Scale v.5.0.
5. Kroner, Uwe, MANSY, JEAN-LOUIS, Mazur, Stanisław, Paweł, Aleksandrowski, Hann, Horst, Huckriede, Hermann, Lacquement, Fréderic, Lamarche, Juliette, Ledru, Patrick, PHARAO, TIMOTHY, ZEDLER, HUBERT, Zeh, Armin, Zulauf, Gernold, Variscan Tectonics, In book: The Geology of Central Europe, volume 1: Precambrian and Palaeozoic, Edition: 1, Chapter: Variscan Tectonics, Publisher: The Geological Society, Editors: Tom McCann, pp.599-664,

2019 Late Harvest Chenin Blanc Update

This past year, 2019, we left a small amount of clusters on our vine with the thought of making a late harvest Chenin Blanc. I wrote two blogs about it:

• Last Harvest of the Year
• 2019 Late Harvest Chenin Blanc Next Steps

Initially, we were quite worried that the wine would be very dark in color. Here is a pictorial recap of what the initial juice looked like:

We began the fermentation on November 25 and stopped the fermentation at approximately 6 Brix which is about 50 g/L of residual sugar. We then added some sulfur dioxide to 0.8 g/L free, and stored it in a 35 degree F fermentation chamber. Yesterday, we took out some wine to test and the wine looked like this shown in the glass on the left.
The numbers for this late harvest wine are:
pH = 3.75
TA = 10.5 g/L
The aromas were of an undertone of tropical fruits. When we tasted it, we got a mixture of tropical fruits and stone fruits.

Vintage 2020: February

This winter has been the warmest that I have experienced since we began growing grapevines. We have not been immune to some of the bad weather that has been rolling across the U.S. and on Friday, we had howling winds with gusts reaching 60 mph! Other than that, we have been working in the vineyard, trying to put ourselves in a good position with pruning done much sooner than we did last year. So, our task for February is to cut all of the tendrils and free the canes from the ties that we tethered the canes with last growing season. This will make pruning in March and removing the wood much easier. Our friends came to help us and put us in a good place with the tendril pruning. While we were doing the tendril removal, we came upon this weird looking, cottony "stuff".

We did some research on the internet but didn't find anything conclusive, but it doesn't look like a good thing so we will get rid of it.

2016 Agathe Bursin Strangenburg Pinot Noir

We are on a mission to understand the Alsace Wine Region and that means tasting through Alsatian wines. My husband bought this 2016 Agathe Bursin Strangenburg Pinot Noir for that purpose. We initially tasted it with Mediterranean style chicken thighs and we immediately liked the wine. It was inky purple colored in the glass the flavors were of black currents with a spicy yet, silky finish.
I learned online that Agathe Bursin, since taking over the family domaine in 2000, has rightly garnered a reputation as one of Alsace’s “comets in the sky”.
Agathe’s Domaine now totals around 5.5 hectares, split over the Grand Cru Zinnkoepflé and the Lieux-dits Bollenberg, Dirstelberg, Strangenberg, all around her home village of Westhalten near Colmar. Quantities from the 5ha estate are small and demand is high making the wines sell out fast.

To make the Pinot Noir, the grapes are hand picked then partially de-stemmed (40% – 60% depending on the vintage). There is no cold soak; fermentation begins in stainless steel tanks with eight days of maceration (longer would lead to the wine being too vegetal) before being transferred into used 228 litre pièces to complete the two months of fermentation. Maturation is for 20 months.
References:
1. Terroirs, Saturday 10th March, 2018 - Meet winemaker Agathe Bursin from Alsace.
2. WoodWinters: wines and whiskies, Agathe Bursin.
3. Frankly Wines, Fruit and Balance [Alsace Vault Vol. 1].

Alsace Part 2: The Geology - The Location of the Upper Rhine Graben

I ended the previous blog on the Geology of Alsace with an illustration of the diversity of soil types that occur in the Alsace wine region.
Little did I know that when I said that I would write a blog about the Geology of the Alsace that I was embarking on an adventure that would take me back in time some 380 million years ago when the continental land masses were in a state of flux and the world as we know it today was still being jigsaw-puzzled together.
The region of Alsace is located on a geological feature called a graben. A graben is the German word for a grave-like trench.¹ The Upper Rhine Graben (URG), where Alsace is located, is part of the 1100‐km‐long European Cenozoic rift system which formed some 50 milion years ago.²
First, in order to understand where the Upper Rhine Graben (URG) is located we need to get a 35,000 foot view of the area:³

In the illustration above, the URG is the area shown in the rectangle. The URG is bordered by the Rhenish Massif to the north and the Jura Mountains to the south. It has a length of some 300 km, extending from Basel in the south to near Mainz in the north and a width between 30-40 km.³

In the above illustration, the left side shows a closeup of the area in the rectangle in the first illustration. This is the Upper Rhine graben.³ The cross hatched areas in that illustration shows something that the inset key identifies as "the basement".
Our major focus will be on the area shown on the right side, the southern URG, flanked by two main mountain ranges, the Black Forest Mountains on the east and the Vosges Mountains on the west.² It's a little strange that the cross hatched area, known as the basement is the location of the Vosges and Black Forest Mountains, but that is because those areas are of very ancient origin.
This will be the focus of the upcoming blogs, an area known as the Southern Upper Rhine Graben, what the various soil types are and when they were formed.
References:
1. James E. Wilson, Terroir The Role of Geology, Climate and Culture in the Making of French Wines, Reed Consumer Books Limited, 1998, ppg 82-107.
2. Yair Rotstein, Marc Schaming, Tectonic implications of faulting styles along a rift margin: The boundary between the Rhine Graben and the Vosges Mountains, Tectonics, 04 March 2008, https://doi.org/10.1029/2007TC002149.
3. Markus E. Schumacher, Upper Rhine Graben: Role of preexisting structures during rift evolution, TECTONICS, VOL. 21, NO. 1, 1006, 10.1029/2001TC900022, 2002.
4. Jeanne Vidal, Albert Genter, Overview of naturally permeable fractured reservoirs in the central and southern Upper Rhine Graben: Insights from geothermal wells, Geothermics, 74 (2018) 57–73.
5. Vincent Maurer, Coralie Aichholzer, Alexandre Richard, Pauline Harlé, Régis Hehn, Albert Genter, Philippe Duringer, Geothermal reservoir temperature estimation derived from gradient wells in a continental rift context (Upper Rhine Graben), PROCEEDINGS, 43rd Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 12-14, 2018.
6. Etienne Skrzypek, Karel Schulmann, Anne-Sophie Tabaud and Jean-Bernard Edel, (Palaeozoic evolution of the Variscan Vosges Mountains) in K., Martınez Catalan, J. R., Lardeaux, J. M., Janousek,V.&Oggiano, G. (eds) The Variscan Orogeny: Extent, Timescale and the Formation of the European Crust, Geological Society, London, Special Publications, 405, http://dx.doi.org/10.1144/SP405.8, The Geological Society of London 2014.