Gaining visibility into an individual barrel’s free SO2 level is how we identify and solve issues in outlier barrels. The impact it brings to wineries goes up as your wine value goes up. In this article, we will look at three things you can do to make the most of your current resources.
Establish a strong quality control system for barrel SO2 additions
Mistakes can happen during barrel work, particularly with SO2 additions — it’s a repetitive process with many details to get right, and it’s easy for workers to get distracted. Double-adding, miss-adding, miscalculating the addition, grabbing the wrong additives, forgetting to stir, and the list goes on.
Having a strong system of post-addition checks in place increases the visibility of whether the additions achieved free SO2 targets, helping to catch not only addition mistakes but also barrels with microbial issues. It is the last line of defense before these problems progress into barrel downgrades or wine spoilage, and also provides insights to improve your current protocols such as refining your addition multipliers.
How to start? If you have limited lab & technology resources, some spot checks on individual barrels after additions is a good starting point. It is recommended that spot checks are done based on individual barrel sampling since composite sampling decreases the chance of identifying outliers. Barrels can be selected randomly, on a rotation basis, or based on their value.
If you have more resources available, you can increase the number of post-addition samples. With the help of technology such as the BarrelWise FS1, the post-addition checking protocols can be even more extensive and structured, based on barrel history of measurements and additions.
Structure your sampling strategy based on wine value
Are you investing more effort where the value is higher? You should.
Structuring your sampling program based on wine value increases visibility where it brings more return on investment. The common sampling method is Uniform Rate Sampling, where you test the same percentage across all lots. This method is good for wineries that have most lots within the same value range.
How about wineries with high-tier barrels that are worth a few times more than low-tier ones? We suggest Mixed Rate Sampling method, where you apply a higher sampling rate for higher-value lots.
It’s also worth to note, for wineries that produce premium tiers and above, shifting to individual barrel sampling will boost the effectiveness of catching problematic barrels, making the above strategies even more impactful.
Before moving on, we have to mention a clever method implemented by one of our customers — Dynamic Rate Sampling — you start with a lower sampling rate (says, 5%), and if the results fall out of the expected range, test another 5%. This is such an efficient method since it keeps the starting sampling rate low, but increases where there is a sign of outliers (i.e. barrels with higher risks). And this method is easy to be combined with others; for example, you can do 100% for high-tier lots, conditional starting at 5% for mid-tier lots, and 2% for low-tier lots.
Consider a periodic barrel audit
A sweeping barrel audit is a great way to gain visibility into the current free SO₂ levels of all barrels.
This is extremely beneficial if you use minimal rack & return during barrel aging, or if you produce Barrel-fermented Chardonnay which is prone to have more free SO2 outliers. Pre-harvest is also a good occasion if you expect to slow down in testing free SO2 during harvest.
A barrel audit can be done based on your current resources and production volume. If you have limited capacity, go with a lower sampling rate, or based on wine value. If you have a more efficient analysis setup and your production level is not massive, it is ideal to test all barrels, and you can time this to special event such as pre-harvest, post-harvest, and post- Malolactic Fermentation completion.
Again, when screening for issues, go with individual barrel sampling instead of composite sampling, ALWAYS.
Here is a recent story of a winery doing a barrel audit and seeing the value of the granular level of data and how it powers decision-making.
Closing Notes on Visibility in wine quality control
Actionable visibility is the best visibility, especially when it can identify problems for intervention and save significant revenue loss for your winery. It starts with having a clear goal and requires a well-thought-out strategy, a right system and technology in place to achieve it.
Visibility is one of two pillars of an effective barrel management program. To know more about the other pillar — Time, read about it here.
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