Refining Pinot Gris
New molecular filtration technology elevates wine’s salable quality
Challenge
Faced with a particularly phenolic 2024 Marlborough Pinot Gris, winemaker, grower and Cleomont Vineyards owner, Digger Hennessy, applied various techniques to reduce the wine’s excessive bitterness and enhance its sweetness. Although the results were relatively successful and the wine could have been deemed commercially ready, a lingering astringency remained.
“A lot of the wines this year were quite phenolic to the point where I actually arrested fermentation a little bit earlier than I normally would, just to keep some sweetness in the wine,” says Hennessy.
“I did numerous fining trials using products I’d normally use which got rid of most of the phenolics but, there was still this one little hard edge. I was getting reluctant to throw anymore fining agents at it as I thought it would be too strippy – and then came the opportunity to run it on the bench.”
Local service provider, Vintech Pacific, introduced Hennessy to the opportunity to trial amaea PFx, a new molecular filtration technology aimed at reducing bitterness to help enhance wine’s salable quality.
Solution
amaea PFx uses molecularly imprinted polymers (MIPs) in a filtration system to selectively capture the phenolic compounds responsible for bitterness and astringency.
During the bench trial, Hennessy and his team established the optimal dose and flow rates—factors determining contact time and available capture sites.
Given that only a light touch was needed, the wine was recirculated through the tank during filtration. The team paused at set intervals for tastings, and under Hennessy’s guidance, decided when to stop the treatment: “The advantages of the technology is there are no hard and fast lines, it’s just a matter of where do we go.”
Hennessy was impressed with the outcome: “The wine didn’t need a huge treatment. It got rid of the very annoying bitterness on the back palate that we were struggling to get out. The MIP treatment made it a lot smoother and now I’m happy with it.”
Though the Pinot Gris could have been approved for bottling prior to treatment, amaea PFx’s ability to reduce bitterness gave the wine wider appeal explains Hennessy: “I think that slight astringency at the end would have offended someone who is more picky about their wine and it would have been a problem. If that was gone for me, that made it more commercially acceptable.”
Results
The finished Pinot Gris was independently reviewed, receiving a score of 93 – noted as having outstanding quality showing varietal purity and exemplifying regional type – and was successfully sold to an existing supplier.
Hennessy sees significant potential for amaea’s MIP technology in the industry: “I think there will be a huge number of things we can trial this with. My perception is that we are being much more surgical with removing the fractions that we want to get rid of. Whereas to achieve that using just protein fining tends to be a bit of a blunt, more of a sledgehammer than a scalpel [approach]. My feeling is that this technique will be much better at getting rid of what we want [to remove] and actually retain what we would like to keep.”
Treatment summary
Wine varietal: 2024 Marlborough Pinot Gris
Volume of wine processed: 24,000 L
Treatment duration: 20 minutes
Date of treatment: September 2024
Applied dose rate: 0.83 g/L
Applied flow rate: 125 CV/hr
Who conducted the treatment: Vintech Pacific
amaea solution: amaea PFx
About Digger Hennessy
Owner of Cleomont Vineyards, Bill (Digger) Hennessy brings with him over 30 years of winemaking experience. Starting his career in Australia, Digger moved to New Zealand in 1991 and now resides in Marlborough where his expertise is revered and sought after in his role as winemaker at one of the region’s leading winemaking facilities.
About amaea PFx
amaea PFx provides a selective, sustainable method for palate fining. Using molecularly imprinted polymers (MIPs) in a one-pass filtration system, amaea PFx selectively targets the removal of the phenols impacting mouthfeel. Winemakers select suitable treatment rates to achieve their ideal sensory profile, while the reusability of the MIPs reduces waste when compared to traditional single-use fining agents.