Monbazillac production at KALIAN
Pressing
The pressing of botrytized grapes is another key step in ensuring the quality of our sweet wines. It must be slow, progressive and adapted to the
profile of the grapes for each vintage. Contrary to a pressing of a dry white wine, it is the last pressings, with the highest pressures, that will provide the highest quality juice with the highest concentration of sugar.
At KALIAN, we have a 24 hectoliter pneumatic press with a closed cage and central drains which
allows us to manage the different lots of grapes coming from each block exactly.
We generally carry out a succession of 5 pressure increases in order to progressively extract the most
concentrated and sweetest juices:
- The first two pressure increases (from 0.2 to 0.5 bar) will release the less concentrated juices, with about 19% in potential of alcohol.
- The two following increases (between 0.5 and 1.9 bar) will allow the extraction of intermediate juices in terms of richness, between 19 and 21% in potential of alcohol.
- Finally, the last step consists of an increase to the maximum pressure (2 bar) and maintaining this pressure for a relatively long time in order to extract the richest juices, between 22 and 24% and sometimes up to 30% in certain years. This last step can be repeated several times depending on the quality of the vintage.
Settling
Settling occurs after pressing and consists in clarifying the juices before the beginning of alcoholic fermentation.
The juices extracted from the press are sent to thermo-controlled stainless steel tanks filled with
inert gas. They will spend 12 to 24 hours there at a temperature close to 5-6°C. The combination of gravity and cold cause the "coarse" particles present in the juice to settle to the bottom of the tank. The next morning the clarified juice is racked into another tank. The juice (or “must”) and its
aromas are thus refined.
Alcoholic fermentation
Alcoholic fermentation or AF is the transformation of the sugar contained in the grapes into alcohol. Saccharomyces cerevisiae, commonly known as baker's yeast, carries out this fermentation.
At KALIAN we ferment most of the Monbazillac lots directly in French oak barrels.
The oak barrel presents multiple advantages:
- First of all, the flexibility in terms of separating lots according to the grape variety, the block and the succession of passes; it is indeed not uncommon for us to have between 20 to 30 different lots at the end of the Monbazillac harvest.
- This container also allows a natural micro-oxygenation very favorable to the yeasts ’activity and thus allowing an easier alcoholic fermentation of the musts.
The remaining batches ferment in stainless steel or concrete tanks (10 to 50 hl tanks).
Generally taking place at temperatures between 15 to 18°C, the alcoholic fermentation can last 3 to 6 weeks depending on the activity of the musts.
Each batch, clearly identified, is monitored daily by measuring the density & temperature. This allows us to monitor the proper progress of the alcoholic fermentations (density measures the decline of the sugar content: a liquid with high sugar content will “weigh” more than a liquid with less sugar and alcohol).
The major risk during the fermentation of sweet wines is indeed the stalling of this fermentation before having reached the desired alcohol-sugar balance. There are different reasons this may occur: excessive sugar content, inhibitory compounds from Botrytis cinerea, and drop in cellar temperature (AF is occuring in November/December).
The target alcohol is between 12.5 and 14.5% ABV depending on the initial richness of the must and the type of harvest. The target residual sugar, on the other hand, is between 110g/l and 150g/l, according to the style of Monbazillac. When the sugar/alcohol balance is reached, we proceed to the cold “mutage” of the wine. “Mutage” is blocking
the residual yeast activity by cold (cold is set at 5°C for about 24 to 48h). After “mutage”, we rack the wine then add a minimal amount of sulfur dioxyde
(SO2) in order to preserve the wine from any further fermentation.
Aging
The majority of batches are then transferred back to barrels for aging. The aging process lasts between 10 to 24 months depending on the batches and the type of Monbazillac desired.
During aging, topping occurs every 15 days in order to limit the contact of the wine with air (oxygen). We may also carry out one or two rackings in order to eliminate the coarsest deposits.
Numerous blind tastings are organized throughout the aging process to determine the blends.
A pre-blending thus takes place in the spring following harvest in order to group together the
closest batches from an organoleptic and analytical point of view.
At the end of the first ten months of aging, we then make a second rigorous selection to determine the relevance of a possible Monbazillac “Sélection de Grains Nobles”. These batches, if selected, will continue to age in barrels for an additional year. Some years, however, we find the potential of the vintage not sufficient enough to produce this cuvée.