So it’s harvest time at our home, Hanwood Estate. The winery is abuzz with excitement as we start the winemaking journey for 2017. But after months of preparation and planning, how do our viticulture and winemaking teams determine when the best time to start picking is? Three factors contribute to this decision: timing, sugar and acid.
Our viticulture team are so familiar with the taste level of ripeness, that they can walk down any row within the vineyard, taste the grapes and know intuitively when to pick; as do the pesky birds. However, there is science behind the timing of harvest to ensure consistency across all the vineyards. The right timing of harvest is the single most important decision a viticulturist and winemaker make each year.
Generally, here in Australia and the rest of the Southern Hemisphere, harvest season is in the first half the year starting in January and going through to the end of May. Harvest time starts in the warmer growing climates like the Hunter Valley in January and works its way down through to the Riverina, across to the Hilltops and Canberra District. Then down to Tumbarumba, Victoria, South Australia and Western Australia with Tasmania being the coldest climate and the last to pick. However, our neighbours in the Northern Hemisphere harvest during the last few months of the year, September through to December.
Firstly, we measure the level of sweetness in the grapes. Grapes grown in our vineyards are much sweeter than the grapes you find the supermarkets as they are smaller in size and more concentrated. Sweetness comes from fructose and sucrose in grapes and is measured in Baume in most states of Australia. It also is a good indicator for the resulting alcohol level of the wine, for example Shiraz grapes with a reading of 13 Be (Baume) will equate to approx. 13% ABV once processed.
There are many advanced tools for measuring Baume, but the most commonly known tool is a refractometer. Viticulturists and winemakers will check the fruit sweetness using this tool every week leading up to the harvest, and then every day until ready.
Once we determine the sugar level our teams will assess the tannin ripeness to ensure the grapes are just right before picking without any bitterness. Tannin ripeness refers to the ripeness level of the seeds, skin and stems. When ripe, the seeds and stems will be less bitter and will change colour from green to yellowish/brown. The skin will be full and bright but may start to soften as the amount of juice released by the grape increases and with that the flavour intensity and tannin levels. Tannin ripeness is key to making an exceptional wine as it will impact on the wines finish, structure and overall feel in the mouth.
Once the grapes reach the desired sugar, tannin and flavour profile it is time to pick.
Happy harvest time!