Why winemakers are central to successful MIP applications
Wine tools have evolved
Winemakers have been developing and evolving their craft for over six thousand years [1]. As human cultures explored greater viticulture and winemaking abilities, they adopted new technologies, built more and larger facilities, and grew more grapes to meet demand.
Very little has changed for winemaking in the last several millennia other than winemakers continuing to gain more control over the process for consistency and stylistic expression. The greatest developments in wine technology have occurred during the last 500 years and have resulted in greater overall wine quality.
What are MIPs and how do they work?
Molecularly imprinted polymers (MIPs) are individual polymer agglomerations built around a specific target compound, as a template. If you are familiar with the lost wax casting process in jewelry making, think of MIPs in the same way. In this case, the template molecule serves as the material that leaves the intricate detail in the polymer structure.
MIP design
Target molecules identified
MIP designed to capture target molecules
Highly targeted filtration.
In your hand, MIPs look like grains of sand and each grain has several million templated binding sites, inside and out. Under an electron microscope, MIPs look like a honeycomb, full of pockets in random order.
A fun fact: each gram of MIPs has approximately 1 x 10^18 template sites (yes, that is a quintillion; 1,000,000,000,000,000).
During filtration of wine, compounds that look like the original template molecule are preferentially bound in one of these numerous sites. This means a class of compounds can be targeted based on the template molecule's shape. Other aspects of hydrogen bonding can influence the binding as well, but for simplicity, think shapes.
Compared to other tools, such as reverse osmosis (RO), the function of MIPs is more targeted. RO is a great tool for inclusion or exclusion of certain sizes of compounds and has been used extensively in winemaking over the last 25 years (e.g. acetic acid removal). MIPs are more targeted than membrane applications because they bind preferentially, based on molecular structure, rather than size or charge.
Large-scale filtration applications of MIP technology have not previously been adopted until amaea partnered with a large US based wine company in 2020 to address the wildfire smoke impacts on high value wines. Since then, the wine applications list has grown to treatments for removal of ethyl phenols (Brett character), pyrazines (bell pepper aroma), and polyphenol fining (to replace PVPP), in addition to removal of smoke volatile phenols.
Sensory ties everything together
Winemakers are central to any wine quality treatment. Bench-trials are being conducted in the lab by enologists and technicians to prove out what adjustments need to be made in the life of a young wine. Winemaking teams routinely use sensory surveys to validate whichever treatment is best. When RO is being done in the cellar, a winemaker tastes routinely to verify that the treatment is meeting their goals. MIP treatments are no different, but the results can be.
MIP treatments start with an initial bench trial on a small volume of wine. Two or three dose and flow rates (a measure of the available capture sites and contact time of the wine with the MIPs) are evaluated to give winemakers a chance to evaluate the impacts of multiple treatment options. Winemaker’s feedback is critical to setting the cellar protocol for MIP treatments. The process can be adjusted in real-time at tank side, but a bench trial really helps winemakers to understand the utility of the treatment.
Verification of treatment effectiveness can be completed using analytical methods, usually at a third-party laboratory. Combining these data points with sensory trials are then able to help winemakers verify treatments and understand their individual responsiveness to target compounds.
The case for value preservation
Winemaking is a cost-intensive business. Once quality grapes enter the winery, teams guide product evolution using many steps in a series to preserve and enhance the value of the grapes. Putting the final touches on a wine prior to packaging is a very important part of the process. Selecting finishing wine treatments is a balance between the display of stylistic intention and the practical use of tools to highlight quality and the preserved value of the inputs.
When making final adjustments for stylistic or consumer interests, MIPs can be more useful than most conventional applications as winemakers can tailor the treatment accordingly. In addition, there is less product loss and MIPs eliminate the need for additional labeling of additives and allergens to achieve the same results.
The case for value recovery
Wildfire is catastrophic for wine quality. Depending on the grape variety, fuel sources, distance to the event and the type of wine being made, the results can be overwhelming on the senses. MIP applications for smoke removal are more targeted than conventional RO treatments and don’t damage the structure of the wine to the same degree. In 2021, amaea’s MIP technology was used to salvage the value of high input wines and demonstrated that modifying the flow and dose rate could recover the value of impacted wines. These wines stayed in the program they were initially planned for after MIP treatment.
In an average year, pyrazines can also cover up some varietal fruit with distracting green aromas. amaea’s MIP technology has recently been applied to this problem as well, enhancing the fruit and unmasking the varietal characters of Cabernet wines from 2023, a cooler vintage.
More on MIP history
The use of MIP technology began in the 1930’s with chemists interested in understanding differences in the molecular size and structure of chemical solvents [2]. However, the application of MIP technology was primarily confined to the analytical chemistry space where it was used to help concentrate target compounds from environmental samples for laboratory identification [3]. amaea has since cracked the code and has taken MIPs out of the lab setting and into commercial wine production operations.
Author: Torey Arvik, VP of Applied Research
References:
Polyakov MV (1931). "Adsorption properties and structure of silica gel". Zhurnal Fizicheskoi Khimii. 2: S. 799–804.
Tobiszewski M, Mechlinska A, Zygmunt B, Namieśnik J (2009). "Green analytical chemistry in sample preparation for determination of trace organic pollutants". Trends Anal. Chem. 28 (8): 943–951.
About Torey Arvik
Torey Arvik is the Vice President of Applied Research at amaea. With over 20 years of industry experience, Arvik is a professional wine industry scientist with expertise in biotechnology, laboratory and product quality management.
Torey earned his Master’s and Doctoral degrees in Food Science & Technology and holds a Bachelor of Science degree in Biology. He has played critical roles in the California wine industry. Initially, through the development of DNA-based quality assurance testing tools for wineries, and then, as the founding research & development scientist at Jackson Family Wines.
Torey volunteers as a board member and is the current Secretary / Treasurer for the American Society of Enology & Viticulture, the largest professional wine society in the US (and Japan). He also chairs the Gold Standard Group, a regional community of technical managers and vendors in the wine industry who are dedicated to finding solutions to common issues.