The Basics

Cellaring is about aging a fermented young wine until it is mature and, hopefully, drinkable. Wine maturation is about melding different evolving flavors into a harmonious blend. We believe

The evolution depends significantly on the amount of oxygen the maturing wine is absorbing as it ages,
Achieving harmony depends on the length of time of oxygen exposure (the longer, the better), and
The longer the wine is exposed to oxygen, the higher the chance of spoilage organisms or oxygen destroying it.

So, you balance a long time to achieve harmony with a short time to prevent spoilage. All depends on how long you are willing to wait and how much effort you spend on sanitation.

Wine matures in a combination vessels with different transmission rates for oxygen and different propensities for sanitation :

Steel tanks: They do not allow any oxygen transmission. But large tanks are often equipped with micro-oxygen injectors, thus enabling flexible control of oxygen uptake. Steel tanks are easy to clean and sanitize
Oak barrels: Standard 60-gallon oak barrels transmit around 8 mg of oxygen per liter of wine per year (French barrel) and 11 mg/LY (American Oak), i.e., 8-11 ppm/Year. Barrels are cumbersome to clean.
Bottles: Corked bottles transmit around 1 mg of oxygen per liter of wine per year. Sanitation is no issue because they are single-use.

We have matured our wine in French oak barrels for around three years and corked bottles for another five years after that. We limit extra oxygen exposure during barrel maintenance, and we are meticulous about sanitation. In contrast, large-scale wineries prefer steel tanks and accelerated maturation to get their wine to market fast to limit costly inventory. We start drinking our wine only 6-8 years after the grapes are harvested, and we expect it to improve quality in the bottle for another 5-15 years. In other words, we only find out ten years after harvest and wine-making whether we did a good job (we find out much faster when we do a lousy job!) – thus the need to keep good records and the slow learning process. This also translates our annual production of 2-3 barrels into a required cellaring capacity of 8-10 barrels and over 8,000 bottles (more than we originally anticipated).

Cellaring process

Cellaring comprises four interlinked activities:

Elevage: We age our wine for three years in barrels. During this time, the barrels need to be topped up every 4-6 weeks to compensate for evaporation. We also need to check on the progress of the Malolactic fermentation and consider adding sulfur to prevent contamination. Finally, we need to make adjustments if required.
Adjustments - there are four basic types of adjustments: Filtering, Fining, Cold Stabilization, and Racking & Blending.
Bottling & Maturation: Before bottling, the wine in the mixing tank needs final adjustments in SO2 (to prevent spoilage) and possibly in CO2 (to compensate for too much or too little aeration during wine-making and cellaring). Then the wine is poured into bottles, the bottles are corked, capped, and labeled, and finally, the wine is aged in the bottles for another 3-5 years before it is ready for consumption.
Barrel/Tank Management is about selecting and buying barrels and tanks, cleaning them after use (i.e., following a Racking operation), and storing unused barrels until they are needed again.

We split this section into the following ten pages:

Barrel & Tank Management: How we select tanks and barrels, how we keep them in good shape and how long we use them.
Elevage: We monitor how the wine ages in the barrels or tanks, top up the barrels because the water in wine evaporates through the wood, and replenish the sulfur content to prevent contamination. Every 4-6 weeks, when we check, we have the opportunity to make adjustments: Filtering, Fining, Cold Stabilization, Racking & Blending, as explained in the following pages. Barrel aging is complete when the wine is judged ready for bottling.
Monitoring Malolactic Fermentation: This page describes how we monitor the progress and completion of the Malolactic Fermentation in the cellar.
Fining: We can remove specific chemical substances in the wine by adding specific fining agents which bind to these substances and aggregate into large molecules, which precipitate into sediment and can then be removed by racking
Filtering: We can filter the wine conventionally to remove large particles or process it through a reverse osmosis filter to remove only the smallest particles.
Cold Stabilization: We can remove certain chemical substances by cooling the wine to just above 30 dF. Keeping the wine at that temperature for a few days will make these chemicals crystallize and precipitate. Then we remove the sediment by racking.
Other Adjustments: This is a grab bag for dealing with other wine-faults
Racking & Blending: Racking is siphoning the wine from a barrel into a temporary holding tank, leaving the sediments behind. Then the residues are removed, the barrel is cleaned, and the wine is poured back in. Racking can be followed by blending. We can blend wine from different barrels or tanks to create more complex wines or cover up wine faults that are only apparent in higher concentrations. To blend, we rack the wine from different tanks or barrels into a blending tank, mix and then pour the mixture back into clean barrels or tanks.
Bottling & Labelling: Before we bottle, we give the wine a final dose of SO2 and check the dissolved CO2 level. Then we transfer the wine into bottles and cork and cap the bottles. Finally, we design and print bottle labels and affix them to the bottle
Bottle Storage & Maturation: We store the bottles under temperature and humidity control for a few years until the wine is ready to drink
Cellaring Summaries: a summary of how we treated each vintage in the cellar.

The graphic on the right illustrates the differences in the cellaring process across vintages 2009-2015. The height of each bar reflects the relative size (in lbs) of each harvest. Note that the number of bottles does not correlate well with the harvest size because we blended some vintages with purchased fruit (e.g., Merlot in 2012) or wine from other vintages. The brown and the grey fields reflect the time allocated for barrel aging and bottle aging. Note, even after release for consumption, the wine in the bottles continues to improve for years until it reaches its peak value, and after that, it slowly deteriorates. From harvest to peak value takes 8 to 15 years. The more tannic and oxygen-deprived the wine, the longer it takes to reach its full potential.

Until 2016 we used surplus wine from one year to serve as top-up wine for the subsequent vintage. We then abandoned this practice because it carried spoilage organisms from one vintage to the next. The following graphic illustrates how the different vintages from 2009 to 2015 are linked across the elevages. Top-up wines were used across vintages, and portions of wine from surplus years (e.g., 2012) were used later to compensate for shortages in years when the harvest was not big enough to fill one or two barrels. This tracking is essential for determining the final composition of the wine is when it gets bottled each year. The graphic also shows what adjustments have been made to the wine during the elevage.

Starting with the 2016 vintage, the process became more complicated. We fermented different varietals and blended them during cellaring.

We needed to replace our data management in spreadsheets with a relational database. We treat each barrel and tank as a separate "cellar batch" in the database. We then compute weighted averages by volume across all cellar batches belonging to a particular vintage. The following screenshot from the Compare Vintages layout summarizes the collected data

Note that we collected relatively little data in the early years, and the data for 2019 and later is incomplete because these vintages are still maturing in barrels.

Following is a short recap of how our cellar management evolved:

For the 2009 vintage, our first year, we used only minimal SO2 for sanitation, and we did not inoculate for malolactic fermentation. 750 bottles.
For the 2010-13 vintages, we slowly increased SO2 additions as we noticed some barrel contaminations, and we improved our barrel washing equipment. We also experimented with adding egg whites for fining before bottling. Bottle counts were 500, 420, 540, and 500.
For the 2014-16 vintages, we inoculated for malolactic fermentation (we mixed results). We continued to increase SO2 additions to fight contaminations, and we added tartaric acids to compensate for the low acidity in the grapes (even overdoing it for 2015!). We fined and used a reverse osmosis filter to fight contaminations. In retrospect, too much intervention. Bottle counts were 500, 250, and 780.
For the 2017 & 18 vintages, we intensified our sanitation efforts by introducing dedicated topup tanks and a new steam barrel washer. We continued inoculating for malolactic fermentation. We continued our fining and reverse osmosis treatments while reducing SO2 additions. Bottle counts were 440 and 860.
The 2019-21 vintages are still in the barrels. We continued to strengthen our sanitation efforts and reduce interventions (no fining, no malolactic inoculation, minimal SO2 additions, etc.)

In a nutshell, we learned to improve sanitation and reduce interventions. The following pages provide more detail

Here is a link to a pdf-file of the Cellar section as of July 16, 2022

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Last updated: May 25, 2022