The Block lab is working in several areas related to wine.  First, we are continuing our work with the Oberholster lab trying to gain a deeper understanding of phenolic extraction in red wines to be able to control the finished wine phenolic profile more efficiently.  Over the last decade, we have examined the impact of cap and juice temperature on phenolic extraction, as well as the impact of cap management (also in conjunction with E. & J. Gallo Winery).  What we found was that skin extraction happens early in the fermentation and the extent of extraction is not very temperature dependent—though too high a temperature seems to lead to anthocyanin degradation.  Seed extraction happens later in the fermentation and is highly temperature dependent.  Cap management, on the other hand, does not seem to have a large impact, though this finding at the 120 L scale (in our “TJ” fermentors) seemed to hold sometimes at larger scales, but not always.  We found instances on a commercial scale where no cap management led to fully extracted wines and other instances where the result was a rosé. 

This discrepancy led our labs to develop combined computational fluid dynamics (CFD) and yeast cell growth models to gain a deeper understanding.  We found that volume or scale were not as important as the geometry of the fermentor.  When the ratio of the height of the liquid under the cap to the surface area of the bottom of the cap was smaller, no external cap management was needed, while more cap management was necessary for taller, skinnier tanks to get the same extraction.  Having a model to predict the outcome of phenolic extraction has the potential to be a terrific winemaking tool because you could enter the grape characteristics and desired final phenolic profile into the model and get suggestions on the best combination of processing choices.  However, measuring these grape characteristics, like total phenolics and cell wall composition, are usually very time-consuming.  Therefore, recently we explored using hyperspectral imaging to noninvasively measure these characteristics on intact grapes.  This could be done when grapes enter the winery or even prior to harvest using a tractor-mounted camera in the vineyard.  This work is still in its early stages, but we have some promising results.  Finally, for phenolic extraction, knowing the desired phenolic profile would be more straightforward, if we understood how individual phenolic molecules impacted mouthfeel.  This is the topic of our current research, again with the Oberholster lab. 

Along with phenolic extraction, we are working with the Runnebaum lab to figure out how to recycle cleaning and sanitizing solutions, both the water and chemicals, as many times as possible in a winery setting.  This will be especially important with changing water regulations in California, and the recent completion of our new Clean-in-Place (CIP) system in the Teaching and Research Winery will enable us to test our ideas at pilot scale as early as this year. 

Recently, about 80% of my laboratory research has been focused on another type of fermentation—that of cultivated meat.  That is, we are working on growing animal cells in a fermentor instead of on an animal.  This is a very new field and requires a lot of expertise in fermentation optimization in order to reduce costs but maintain quality and safety.  We hope this research will help fill some of the projected supply gap in meat production over the next 25 years, along with research on plant- based and fungal-based meat production.  I have led a campus group of around 50 researchers working on cultivated meat for the last 5 years (and received the first US federal funding in this area) and more recently launched a larger umbrella center, the integrative Center for Alternative Meat and Protein (iCAMP), at UC Davis and 5 partner institutions, that examines all routes to alternative meat production.