Co-Inoculation as a risk-mitigation strategy in malolactic fermentation

I have previously discussed the malolactic fermentation (MLF) of wine both as a 'natural" occurrence and being induced through inoculation. In that treatment I discussed MLF as occurring after alcoholic fermentation (AF) in a sequential process. The gap between the conclusion of AF and the initiation of MLF is a risky period as no sulfur can be applied to the wine due to its toxic effect on the bacteria that facilitate the latter. During this time, the wine is exposed to the potential of oxidation and attack by spoilage organisms. While inoculation reduces the duration of the gap, it does not completely eliminate the risk.

Under the "right" circumstances, the lactic acid bacteria (LAB) can themselves pose a risk to wine quality. In a normal AF, all of the fermented sugars are consumed by the yeasts, with residual sugars coming in at < 2g/l. Also, the fermented sugars will have been fully consumed prior to the full depletion of the malic acid. In cases of stuck or sluggish fermentations, however, the malic acid may be fully depleted while fermentable sugars are still available. LABs are heterofermentative and while they preferentially consume malic and citric acids, they "possess the metabolic machinery to utilize glucose and fructose for the production of energy." The by-product of such energy production is acetic acid, an undesirable characteristic in wine.

Co-inocualtion, an emerging approach,  has been employed as a strategy to minimize the identified risks. The figure below shows MLF considerations and the options in the inoculation space.

Co-inoculation involves introducing selected LAB into the wine within 12 to 48 hours of its inoculation with AF yeasts. If the LAB is introduced earlier than 12 hours post yeast inoculation, 99% of the viable cells would be killed off by free sulfites. In the early stages of AF, however, the yeasts produce compounds which detoxify the free sulfites, rendering the environment more hospitable for the LAB. 

Advantages of Co-inoculation

Following are some of the benefits associated with co-inoculation:

• Better control over the winemaking process in terms of time management
• Shorter AF-MLF cycle
• Bacteria are introduced into a low-ethanol, high-nutrient environment with the lowest pH the wine will probably experience
• Bacterial activity is suppressed during active fermentation but cells acclimatize their membranes to the rising alcohol during this time
• Microbiological activity of both the yeasts and the bacteria work to limit  development of contaminating organisms 
• As yeasts begin to die at the end of AF, they release nutrients into the wine just as malic bacterial production begins to transition from lag to log phase
• When MLF occurs under the reductive conditions of AF, lower levels of diacetyl and higher levels of fruity esters manifest in the wine. 

©Wine -- Mise en abyme

Château Léoville Las Cases vertical tasting: 1975 - 2005 (selected vintages)

With the Léoville Las Cases background in the rearview mirror, I now turn to the actual tasting of the wines. The event was held on May 10th at Vineyard Wine Company (Lake Mary FL) and the participants are pictured below.

The wines included in the tasting are shown in the table below.  Petit Verdot was totally eliminated from the Grand Vin blend by at least 1996. Petit Verdot was a part of the blend for the Clos du Marquis wines tasted. The wines were tasted youngest to oldest overall and within flights.

Table 1. Léoville Las Cases tasting lineup by variety and estate

Year	Leoville	Marquis	Cabernet Sauvignon (%)	Merlot (%)	Petit Verdot (%)	Cabernet Franc (%)
2005	X		88	7		5
		X	50	37	1	12
2004	X		76	13		11
2000	X		77	9		14
		X	68	24	5	3
1998	X		76	15		9
1996	X		70	14		16
1994	X		60	24	4	12
1990	X		43	29	7	21
1986	X		66	19	5	11
1983	X		73	11	5	11
1978	X		55	19	3	23
1975	X		60	30	3	7

The 2000s Flight

2005 Léoville Las Cases

Ideal conditions in this year resulted in highly concentrated and perfectly balanced grapes.

This wine still needs time. A mix of black and red fruit on the nose along with tobacco, limestone, cassis, and mushroom. Forest floor, black and red fruit, mineral, and leather on the palate. Tannic monster. — Author

Not ready. Lots of tart cherries and you can tell the fruit is not quite developed yet and will get better with 10 years or more — Brian

2005 Clos du Marquis

Black and red fruit on the nose along with tobacco and graphite.  Nose carries through to the palate. The volume of Merlot versus the percentage in the Grand Vin is evident herein. Silky, integrated tannins. Balanced with a lengthy finish. — Author

Medium fruit and a little quick on the palate, slightly green notes, tannic, needs more time — Brian

2004 Léoville Las Cases*

The Grand Vin grapes were perfectly balanced and beautifully fresh.

This wine had a somewhat Pauillac nose with pencil shavings, black and red fruit, earth and spice prominent. Graphite and pencil shavings on the palate. Still somewhat tannic. — Author

For me the best wine of the flight, perfume on the nose, rose petals and potpourri, rocky tannins with cherries — Brian

2000 Léoville Las Cases

Excellent conditions allowed the harvesting of perfectly balanced grapes rich in phenolic compounds.

Concentrated intense dark fruit along with cedar wood, leather, and graphite on the nose.Dark fruits, currants, spice, and minerality on the palate. Full-bodied with grippy tannins and a lengthy finish. — Author

Luxardo cherries, balanced, tobacco notes and graphite – showing Pauillac almost, one of the better 2000 wines I have had this year — Brian

2000 Clos du Marquis

Dried fruits, cedar, mocha, graphite, and cassis on the nose. Sour cherries on the palate and a lengthy finish. — Author.

Still a great wine but with a shorter finish than the Leoville. A very balanced wine with less fruit than the Leoville — Brian

The 1990s Flight

1998 Léoville Las Cases

Early bud break and flowering with a hot, dry August favoring good ripening.

Bright black fruit, cassis, and pencil shavings on the nose along with vanilla, spice, truffle, leather and tobacco. Full-bodied on the palate with red cherries and charcoal. Soft tannins and a lengthy finish. — Author

Fruit was mediocre, a lot of tannins with a chemical nose — Brian

1996 Léoville Las Cases

Grapes, particularly Cabernet Sauvignon, of extraordinary concentration. Perfectly balanced and highly aromatic.

Olives, tar, cedar, violets, dark fruits, cedar box and leather on the nose. Medium weight on the palate. Savory. Balanced. Smooth long finish. — Author

It’s a 1996!  Exactly what I thought it would be – excellent, thyme and sage notes blended with great cherry fruit and pencil lead. Tannin and acid matching and balanced. — Brian

1994 Léoville Las Cases

Rains and cool September temperatures disrupted the ideal conditions experienced until then.

Dry red and black fruit, cigar box, cedar, leather, and bell pepper on the nose. Creamy on the palate but with a hole in the middle. Fine tannins and a lengthy finish --- Author

Very short wine, still a very clean wine but fruit was less pronounced. Easy to drink but not complex — Brian

1990 Léoville Las Cases*

Perfectly ripe grapes.

Pencil lead, leather, and blackberry on the nose. Tertiary-rich. Elegant and balanced -- Author

Long lasting on palate with a perfect finish. This fruit was shocking as it was more ripe strawberry then cherry.  Fantastic wine which shows that these wines need all the age they can get — Brian

The 1980s Flight

1986 Léoville Las Cases*

Cabernet Sauvignon exceptionally ripe and concentrated.

Blackcurrants, leather, cassis, graphite, and rose petals on the nose. Balanced, persistent, and savory on the palate. Unresolved tannins with lengthy finish -- Author

While an integrated wine, the fruit is declining. Almost a sour fruit at this time — Brian

1983 Léoville Las Cases

Cool and wet spring followed by a hot and stormy July and August. Wet in the first half of September, hot and dry from the 17th on.

Missing fruit. Pencil shavings, cigar box, cassis, and barnyard on the nose. Medium weight with integrated tannins -- Author

All tertiary flavors at this point. Lots of tannin and acid. Very different from the other 1983s I have had this year — Brian

The 1970s Flight

1978 Léoville Las Cases*

Very dry August and September, following a wet winter and spring, allowed for good ripening.

Tertiary characteristics. Almost elegant. Red fruit along with medicinal character -- Author

Wow, what a wine for the age. Fantastic start and has a cola taste about 5 seconds in and has length, light tannin, and acid – my #1 — Brian

1975 Léoville Las Cases

Despite spring frosts, good growing conditions helped the grapes ripen properly.

Red and black fruits, forest floor, pencil lead, tobacco and leather on the nose. Red fruits and a savoriness on the palate. Balanced with resolved tannins and a lengthy finish -- Author

While it had more tannin and acid than the 1978, it was still light. Sweet tart flavor, with sour cherries but not a complex wine and past its time — Brian

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The asterisks associated with selected wines above indicates the wines of the flights. When evaluated against each other, the 1990 Grand Vin was adjudged the wine of the night.

Overall the wines showed very well with the Clos du Marquis holding its own. These wines show better with the passage of time and are consistent in the representation of non-fruit characters such as pencil lead/graphite, leather, cassis and tobacco. 

The full lineup is shown below.

We will continue our exploration of the Léoville wines with an upcoming tasting of the Barton wines.

©Wine -- Mise en abyme

Château Léoville Las Cases: History, environment, grape-growing, and wines

Having completed our study of the Pauillac region, the Orlando Tasting Group now turns its attention to the St. Julien sub-appellation and the Léoville wines.

History

The three current Léoville estates had a common beginning back in 1638 when Jean de Moytie founded a vineyard on a Medoc gravel ridge and named it Mont Moytie. This estate, along with Margaux and Latour, was the earliest wine producer in the region and remained a unit until the period 1826 to 1844 when it was split into three separate entities. The chart below details the history of the estate up until its dismemberment.

From the 1840s on, the Las Cases branch of the Léoville tree was managed by a succession of family members. Somewhere along the way 20 shares were authorized to account for the total ownership of the enterprise. In 1900 one of those shares was issued to Theophile Skawinski, the estate’s general manger. Skawinski was the great great-grandfather of the current owner and, over the years, the family has set itself the task of acquiring every share that it did not already own. That goal was accomplished in 1994 when the Delon family became the sole owners of the estate.

Léoville Las Cases introduced a new wine — Clos du Marquis — from a different terroir in 1902. In the first two decades of the 21st century the enterprise introduced true second wines for each of its primary labels: Le Petit Lion for Las Cases and La Petit Marquis for Clos du Marquis.

Léoville Las Cases Grape-Growing Environment

Saint Julien, being south of Pauillac, is slightly warmer but still subject to similar climate-modification effects (see chart below). The soil is similarly gravelly but has less clay and limestone.

Leoville Las Cases sources the grapes for its wines from two separate terroirs: A walled vineyard (Grand Clos) for the primary wine and a vineyard 500 yards to the west for the Clos du Marquis.

The Grand Clos extends over two small hills and is the heart of the Las Cases vineyard. It lies in the north of St Julien, bordering on Pauillac, and is separated from Chateau Latour by a small stream. The deep gravel soils rest on clay and sand sub-soils. The aspect is SE. 

The vineyard is divided into seven main blocks and, further, into 125 parcels. Cabernet Sauvignon is planted on the hills while Merlot is planted at the bottom of the slopes. 

The vineyard is farmed organically with sustainability the driving force behind vineyard practices:

• Cover crops between rows to prevent soil erosion and boost soil health 
• Limits on chemical use. Natural products are used to control pests
• Efficient irrigation systems.

Vineyard management practices include::

• Dense planting scheme — forces vines to compete, resulting in lower yields and higher quality
• Pruning and canopy management by hand; allows for precise control
• Each plot harvested at optimal ripeness

Winemaking at Leoville Las Cases

Philosophy

The Chateau seeks to produce wines:

• Representative of their terroirs
• To be consumed during meals 
• With great aging potential
• That improve with age.

Process

The Leoville Las Cases winemaking process is labor-intensive and meticulous and is mostly unchanged from the 19th century. The requirements/steps are as follows:

• Harvesting of high-quality grapes
• These grapes are carefully selected and sorted (including optical sorting (a relatively new innovation)) to ensure that only the best grapes make it into the wine 
• Fermentation vessels include wood, concrete, and stainless steel vats of varying sizes. Eight oak vats are reserved for confiscation of the Grand Vin whike cement tanks are used for all other wines.
• Movement of wines within the cellar is via gravity flow
• Malolactic fermentation occurs in tanks
• Blending is conducted post-MLF but prior to oak aging in order to ensure no oak influence in the construction of the blends
• Wines are allowed to mature post fermentation so that they can develop their complex flavors and aromas. Recently the wine has been aged for 18 months in 90% new French oak
• Beginning in 1987, reverse osmosis technology has been employed during the winemaking process to help extract excess water from the mist. This is, of course, controversial among purists. 

Wines of Léoville Las Cases

Grand Vin de Léoville

This wine has been described by Berry Bros & Ruud as “… arguably the most exotically perfumed wine in the Medoc and this can be partially attributed to the must being fermented at lower-than-average temperatures, which leads to its youthful, aromatic richness being retained. On the palate it is powerful and concentrated and marvelously well-balanced.”

The wine is structured, firm, austere, and powerful with top vintages taking 15 - 20 years to lose its tannic structure. The wine displays intense ripe fruit flavors of black currant, cassis, and wild blackberries with subtle floral aromas and finely grained tannins. Depending on the vintage, it can present a more upright Pauillac profile or a more tender St Julien profile.

The wine is a blend of Cabernet Sauvignon and Cabernet Franc. Between 9000 and 15,000 cases are produced annually.

Le Petit Lion du Marquis de Las Cases

This is a true second wine made from younger vines. The blend is approximately 45% Cabernet Sauvignon, 45% Merlot, and 10% Cabernet Franc. The wine shows dominant black fruit flavors, graphite, minerality, tobacco, and grainy tannins.

The wine is designed to be more accessible.

Clos du Marquis

This wine was first produced in 1902 with grapes secured from the top terroirs of St Julien that was a part of the Léoville historic vineyard. This wine offers a fine expression of the St Julien character: structure, complexity, harmony, distinction, and aging potential.

Annual production of between 4,000 and 8,000 bottles per year.

La Petite Marquise

Young vines from the Clos du Marquis terroirs. 56% Merlot, 44% Cabernet Sauvignon.

I next address our tasting of the wines from this estate.

©Wine -- Mise en abyme