Deciding when to harvest is one of the most critical decisions we make every year at Brennan Vineyards. You need to be 100% sure when you make your final decision to pick. Once you pick the grapes, you can’t put them back on the vine if you made the wrong choice in deciding to harvest.
There are a couple of different ways to sample. You can either do berry sampling or cluster sampling. For both types of sampling, the more samples you have the more accurate your numbers will be. Randomness is the key to obtaining reliable numbers. When berry sampling you need at least 100 berries. You need to take the berries from all over the clusters. You will take berries from the front, back, left, right & bottom of the vine. You will also take berries from clusters you can see and ones you cannot see. It is more time consuming to do berry sampling.
At Brennan Vineyards we do cluster sampling. I’ve read that you need up to 20 clusters to get a reliable number. When I sample, I bring back 5 clusters from each variety for testing and I always sample in the morning. In case you forgot, we live in TEXAS and it is HOT during harvest. You can sample any time of day, but once you chose a time to sample you need to do it at the same time every time.
What are we testing for and looking for? We are looking at two basic chemistry’s of the grapes Brix (sugar level) & pH (strength of the acidity). We are also looking at clues from the grapes themselves. We look at skin color in white grapes. With red grapes, the skin color is harder to determine harvest maturity. Seed color is also a very good indicator for harvest maturity with both red & white grapes.
Once I have the samples, I go back to the winery and turn the samples from clusters to juice. Aroma and juice color are two more things that I use to decide maturity of the grapes.
I mentioned earlier that randomness is the key to obtaining reliable numbers. If you read an article about grape sampling, or have been taught by someone on how to sample grapes, being random is the first and most important factor in getting reliable numbers. I am 100% in agreement with the concept and importance of being random.
In reality, even if you close your eyes to pick berries, it is very difficult to be random. I tried it this way my first several years at Brennan Vineyards. It seemed like every time we harvested the actual numbers were lower than expected and the grapes were not as ripe as we thought. So a few years ago I decided to “randomly” pick the clusters that were not ripe on purpose. Where do you find these? You can’t see the clusters which is why I am looking for them. They are high up in the canopy getting less sunlight and are ripening at a slower pace than the awesome looking grapes that you see in all of our pictures on social media. This method of sampling at Brennan Vineyards has served us well since I came up with this protocol.
The other day we harvested Blue Vineyard Chardonnay. The Brix (sugar) levels were right on 24.0 in the vineyard. The actual Brix level was 24.5 when we tested again in the winery. It is very common for a vineyard grower to say the Brix is 25.0 and it is time to harvest only for the grapes to show up at the winery being 23.0. This has probably happened to every winery in TX more than once.
Although we are very early into 2016 harvest, the grapes are looking great right now. Sugar levels are climbing fairly rapidly due to the high temperatures. Grape quality looks to be above average this year while quantity seems to be just ok. I would prefer this scenario. When it is all said and done, I would rather make less great wine than a lot of average wine.