How do you know when to Pick Grapes for Making Wine?

This is a question that I often get asked at Cellar Door as visitors gaze out over our vineyard in Summer and see the ripening bunches on the vines.

Sampling the grapes is how I work out when the best time will be to pick the grapes for each wine that we make.

I arm myself with a bucket and a pair of snips and collect bunches of grapes from vines growing in each vineyard block. I walk up and down several rows, zig zagging my way up and back rows, randomly snipping off bunches from vines along the entire length of both rows and dropping the bunches into the bucket.

I make sure that I select a mix of bunches that are growing at different spots in the vine canopy. Bunches that are shaded inside the canopy covered entirely by leaves, bunches that are semi-shaded by leaves, and bunches that are unshaded and growing in the full sun.

I sample like this as each bunch will be at different ripeness levels and I need to collect a sample which is representative of all of the vines in that block. As well as sampling the bunches, I pluck berries off bunches as I walk along, tasting the flavours in the berries.

Why is it Important to Pick Grapes at the Right Time?

This is an absolutely critical part of the winemaking process as the harvesting decision, when to pick the grapes, is crucial to making a wine of the quality and in the style that you have been planning for. This is where all of those years of winemaking experience really pays off!

I take bunch samples from up and down a row, and from different growing positions on the vine, and taste berries up and down the rows. I have to sample this way to ensure that my grape sample is representative of the varietal block in the vineyard. Even though all of the vines in a block are the same variety, there is variation in ripeness levels across the block due to variations in soil types across the vineyard, how much sunlight the grape bunches are receiving, and the vigour of the vines.

The tasting gives me an idea overall of the flavours across the block. By analysing the juice from the grape bunches for sugar and acidity, tells me the average ripeness level of the grapes in the block.

I then have a snapshot of what the flavours are and what the overall ripeness levels are, which I can then use to predict how many weeks away harvest is likely to be. I repeat the bunch sampling and berry tasting a week later to get an idea of the rate that ripening is occurring in that block. Then I repeat again the following week, and so on until the block is harvested.

What Time of the day is Best to Pick Grapes?

One of the most best times to pick grapes is when the temperatures are at their coolest, which is either during the night or in the early morning before the day warms up.  is because when the harvest season starts it is still summer and it is hot.

If using a machine harvester, many wineries decide to pick grapes between midnight and early morning because the cooler nighttime temperatures help concentrate and preserve the fresh fruit aromas and flavors and stabilize sugar levels.

If hand picking, wineries start the grape harvest teams at day break and continue on until the day becomes too hot.

What Time of the Year do You Pick Grapes?

Grape picking, also known as grape harvest or vintage, happens usually from late Summer through to mid to late Autumn. We start picking the first grapes here in February and continue on until late April. Each grape variety ripens at a different time.

Do Grapes have to be Ripe to make Wine?

When to pick grapes is one of the most critical decisions a winemaker or grower has to make. The best wines are made from grapes that are ripe, with well developed flavours, and levels of suagr and acidity to make a well structured and flavoursome wine.

The decision is based on few factors, what the sugar content is, what the acid level is, what types of flavours are in the grapes, and what is the weather going to be doing over the next 1 to 2 weeks.  Unlike most fruits, grapes do not continue to ripen after being picked. If picked too early, the resulting wine can be tart and overly herbaceous. If the grapes are picked too late, the wine ends up lacking a good structure as the acid is low, the sugar is high and the alcohol ends up being high.

How do You Pick Grapes?

When it comes to picking grapes, there are two ways that they are picked, by a grape harvesting machine or by people hand picking the bunches off the vines.

Harvesting by machine is the quickest. It is an incredibly efficient way to pick grapes because the grapes go from being on the vine, to being crushed and pumped into a chilled tank within a short period of time. Machine harvesters can operate during the night when the temperatures are coolest. Another reason why machine may end being chosen as the preferred method to pick grapes, is if the weather is predicted to take a turn for the worse, and rain is coming. Heavy rain can spoil ripe grapes so there can be a rush to quickly pick grapes before the rain arrives.

Handpicking is a often a more expensive option as the actual picking of the grapes will take longer than the time it would take to pick them with a machine, and labour costs are high. However, hand picking is often essential for certain styles of wine, such as making a sparkling wine or a delicate Riesling.

So the choice comes down to how much it will cost to pick the grapes, what style of wine is being made, and as always, what the weather is doing over the next 1 to 2 weeks.

Getting it right in the vineyard is the key to success here. Managing a vineyard has it’s challenges, as well as it’s joys. The most important thing is to make sure that you pick your grapes at the right time to make the very best quality wine that you can make. Making a great wine from good quality grapes picked at the right time is much easier job for a winemaker. Trying to make a good wine out of average quality grapes picked at the wrong time is a whole lot of hard work and the end result is a wine of lesser quality, and a wine that is less enjoyable to drink!

Suggested Read:

Here is a link to a UK article which summarises beautifully how picking at the right time enhances wine quality.