Welcome to my first newsletter!

This newsletter is intended to be a monthly short dive into very specific elements of sparkling wine production, this will be based on publicized research and materials and always referenced at the end of the newsletter, with some experience thrown in as reference occasionally. Because it’s not a scholarly article, I’m not writing it formally at all, which I hope you find refreshing. Let me know if you have requests for future topics! With no further ado…

Phenols at the press

Juice handling at the press is arguably one of the most important factors in high quality sparkling wine production. Today I’m going to dive into the biggest reason sparkling producers do things a little different at the press, phenols.

First off, what’s a phenol and why should you care? Phenols are important substances in grapes, they contribute color, tannin, and are oxidative substrates. Your average winemaker is concerned with manipulating, preserving, or eliminating these in basically any wine. Phenols are complex substances that are found in many different forms throughout nature. The phenols winemakers are most concerned with are flavonoids, anthocyanins, and tannins. Flavonoids make up the largest fraction of the total phenols in grapes, they are found primarily in stems, seeds, and skins, and are extracted during maceration. They are responsible for yellow color but also texture and body, these phenols get a lot of attention when you’re talking about red wine making, but make up very little of the total phenols in white wine production as skin maceration is very limited. Anthocyanins are a class of flavonoid compounds found primarily in grape skins and are responsible for blue and red coloring which begins developing during verasion. Some grape varietals classified as teinturier have these compounds in the pulp, making for reddish colored pulp as well. Lastly tannins which are found mostly in skins, stems and seeds and are responsible for dryness, texture, and astringency in wine.

Now that we know what phenols contribute to wine and where they come from, why should we care? One word, foam. Sparkling wine is all about the bubbles/fizz/froth/foam, it’s literally what defines this category of wine. Foam formation and it’s persistence is unquestionably used as an indicator of quality in sparkling wine. We should care about phenols and foam because there is a consensus among research that phenolic compounds reduce foam stability. More foam isn’t necessarily better (think about that bottle that gushed to the ceiling that one time) but less foam is definitely worse.

Phenols can be controlled at the press by being selective about what juice is used for your base wine. Understanding what juice to keep starts with the makeup of the grape. The grape berry itself has a few different chemical composition zones each with their own chemical makeup. Generally there are three zones, the one closest to the seeds (the intermediate zone) contains mostly malic acid and sugar, the next zone away from the seeds (the central zone) contains mostly tartaric acid and sugar, and the last part, just below the skin (the peripheral zone), contains the most potassium, oxidases, aromas, and astringency. When pressing, the central zone has the most fragile cells, which release their juice first, followed by the intermediate zone. The earliest juice released from pressing has the most tartaric and malic acids. As the pressure builds during the press cycle, more potassium and oxidases are released into the juice and the juice gains a higher pH and more aptitude for oxidation due to it’s chemistry and make up.

Knowing this, it doesn’t take a lot of analytical thinking to realize age-worthy sparkling wine should not include much of the hardest press juice, if any. The wine will not age gracefully in tirage or post disgorgement, due to the higher pH and increased oxidation capacity, not to mention the quality of the bubbles will be reduced. For lower cost, quicker to market sparkling wine on the other hand, especially wines that are designed to be expressive, using the hard pressed portions of the juice would be a perfectly acceptable use this juice.

I hope you found this useful! Please let me know if you have any thoughts on this newsletter or requests for future articles. If you feel like you need sparkling winemaking consulting services please reach out to me!

References:

^{Boulton, R. B., Singleton, V. L., Bisson, L. F., & Kunkee, R. E. (2013). Principles and practices of winemaking. Springer Science & Business Media.}

^{Martínez-Lapuente, L., Ayestarán, B., & Guadalupe, Z. (2018). Influence of Wine Chemical Compounds on the Foaming Properties of Sparkling Wines. InTech. doi: 10.5772/intechopen.70859}

^{Zoecklein, B. (2002). A review of Methode Champenois Production. Virginia Cooperative Extension, Publication 463-017W.}