On 26 September, we hosted a seminar with the long title “Comparative tasting of wines aged for over 20 years under cork and screw cap – tasting 15 wines from 5 Australian producers”. After going through an era when corks were challenged by screw caps as the norm for wine bottle stoppers, the pros and cons of each bottle stopper are now widely recognized. But how does each type of stopper actually affect the taste of a wine, or indeed, change the wine at all?In the late 1990s, Australian wine producers were struggling with the quality of corks, leading winemakers in Clare Valley, South Australia to bottle their 2000 Rieslings under screw caps, which were then being used for Chasselas wines in Switzerland. They quickly became popular among winemakers.For the first year or two, some of the early adopters released the same wine with both cork and screw caps. At Village Cellars, we decided to import the wines bottled using both types of stoppers and aged them for a long time in our own temperature-controlled warehouse. We considered the possibility of selling them as a set at a later date, but to be honest, we wanted to taste them for ourselves to see if it there was any difference over time.More than 20 years have passed, and for some of the wines we only had six bottles left. To share this special opportunity as widely as possible, we offered places to 100 people, the maximum number who could taste an appropriate amount of wine from six bottles, and asked Mr. Satoru Mori, a sommelier with an extensive knowledge of Australian wine, to lead a tasting seminar at the Andaz Tokyo.The wines tasted were 2 whites and 3 reds, detailed in the table below. There were 3 wines from 5 different wine producers, one each bottled under cork and screw cap from the same aged vintage, and one from the current vintage under screw cap. A total of 90 bottles of wine were opened two and a half hours before the seminar started. We immediately injected argon gas using WineSave PRO, removed a small amount with a pipette for Mori-san to taste to confirm the wine was in good condition, and then recapped the bottles for opening and pouring into glasses just before serving.Of the 90 bottles, the screw cap wines showed very little difference in bottle age, not to mention the current vintage, even after 20 years. However, when it came to wines stopped with corks, although we were able to select healthy coloured bottles of white wines in the cellar, it was difficult to judge the condition of red wines without opening the bottle. So, beside TCA (cork odour) and excessive oxidation caused by the bottle, there was an undeniable variation in the bottles.The logistics were challenging, with 15 tasting glasses per guest. This meant pouring wine into over 1,500 glasses in total, which had to be delivered in a timely manner to ensure a smooth flow during the seminar. A detailed progress schedule was prepared, and in the workspace next to the seminar venue, under the leadership of a captain who resembled a drill sergeant, the hotel and Village Cellars staff worked with clockwork precision.At the conclusion of the seminar, Mr. Mori summarized the tasting: for wines stopped with corks that were aged and in good condition, the acidity that forms the profile is more integrated, giving greater complexity and sweetness. On the other hand, with screw caps, in addition to not having to worry about cork taint, the wines were balanced and aged evenly, retaining their youthfulness even with aging. In the end, it’s a matter of individual preference, but the decision on which is more suitable should be based on the service conditions and the application (eg opening just a single bottle with friends, or multiple bottles in a hospitality venue) considering the efficiency of opening corks vis a vis screwcap, and uniformity of quality. He reassured us of the potential for aging under screw caps, but still doesn’t think screw cap wines have the same “sex appeal” as wines with cork stoppers today. There was also a request to keep wines under screw cap for another 30 years to see how they age further!After the seminar, regardless of their level of experience with screw cap wines, all participants agreed it was a very interesting tasting, comments that gave us a great deal of pleasure.Wine tasting listC = cork S = screw capGrosset Polish Hill Riesling 2000 (C/S) & 2022 (S current)Leeuwin Estate Art Series Chardonnay 2003 (C/S) & 2019 (S current)d’Arenberg d’Arry’s Original Shiraz - Grenache 2002 (C/S) & 2021 (S current)Elderton Command Single Vineyard Shiraz 2002 (C/S) & 2018 (S current)Mount Langi Ghiran Langi Shiraz 2003 (C/S) & 2019 (S current) Read Mori-san’s comments on all 15 wines and information distributed on the day (Japanese).