Optimising your yield prediction – getting the bunch weights right!
We know that counting bunches as the grapes are growing on the vines is a hugely important part of the vineyard monitoring calendar. A thorough bunch count gets you around 60% of the way to an accurate yield prediction, with the other 40% coming from understanding your bunch weights. After working with many different vineyard managers, we have found that taking steps to optimise your yield prediction means you can consistently get your prediction to within 5% of your actual yield – well worth it! In this post we will focus on optimising those final steps of the yield prediction, and using your intuition, combined with all of the data available, to ensure you get the best prediction possible.
As Luke Spalding, vineyard manager at Everflyht Vineyard in Sussex, told us:
“Without a good yield prediction, it can create a lot of stress for the vineyard team, as harvesting time can get out of control. It also creates stress in the winery when you don’t know how much is coming in or when the harvest is going to stop!”
So…. you have got a good estimate of your bunch count, now how do you get the best estimate of your bunch weights? Let’s talk you through different ways people approach this and how our newly released Sectormentor tools help with each…
Counting bunches at Everflyht Vineyard with Luke Spalding
The art of estimating bunch weights: from early estimates to lag/veraison
The most common method for creating your first yield prediction of the season is to use the average bunch weight from past years combined with current bunch counts. This is good for getting a vague first estimate but we have learnt over many harvests that for lots of sites there is almost no such thing as an ‘average year’ – each year zig-zags quite considerably around the average, so calculating a prediction based on this concept of an average can send you way off! We notice people will often say things like ‘this season is shaping up to be just like 2016’ – so the Yield Predictor now makes it easy to select bunch weights from a particular past season, for making an early prediction of this year’s yield. If current growing patterns remind you of the 2018 season, you can go in and use the average bunch weights from 2018 in your prediction for this year.
Once you hit lag phase or veraison many viticulturists will weigh some bunches to get an early idea of actual bunch weights for this year. At this point, in Sectormentor it’s very easy to update your yield prediction with the average lag/veraison bunch weights from each block (these were entered into the app and then Sectormentor automatically calculates the average for each block) combined with a multiplier appropriate to each block/varietal.
Joel Jorgensen, viticulturist and consultant at Veraison, has been using the new Sectormentor update.
He told us: “Being able to quickly and easily make a prediction that integrates bunch weights from specific past seasons is brilliant. Of course there is no ‘average’ season, but often a season feels similar to a past year, so being shown an estimate of the predicted yield based on historic bunch weights for each block is very powerful.”
We often hear vineyard managers remembering the year with the biggest yield, or recalling painful memories of their worst, lowest yielding year. Knowing what possible extremes might look like, based on past years, presents a more complete picture of what your harvest could look like.
Do the berries look particularly small this year? Or maybe the bunches are some of the heaviest you have seen…
With the Sectormentor Yield Predictor Report you can see the heaviest and lightest bunch weight you’ve ever recorded in each block and we extrapolate from that what this years yield in each block would look like if either of those extremes happened (taking into account how many bunches you’ve counted this year).
These estimation ranges are now standard as part of each yield prediction, helping you to see on a block by block basis what the likely range of yields are. As the season progresses and you update your prediction, this estimation range becomes increasingly useful, as you get a sense for this year in relation to others, with all the numbers at your fingertips.
We spoke to Will Davenport, at Davenport Vineyards in Sussex & Kent, after he’d tried out the new updates:
“Having the high and low estimates really helps us plan tank space effectively as we have a better idea of the upper and lower ranges for yields we can expect from each varietal.”
Joel at Veraison found the estimation range update has made his yield estimates much quicker and easier:
“A good estimation range is also a vital part of creating a yield estimate as so much can change between veraison and harvest, so it’s useful to know best and worst case scenarios as early as possible. I’ve never had this kind of information at my fingertips before – Sectormentor is making it faster and easier to do my job, and helping me to access powerful information that previously took hours of complicated spreadsheets.”
This is about optimising those final steps of the yield prediction, and using your intuition, combined with all of the data available, to ensure you get the best prediction possible.
Example shot of the estimation range in the Yield Prediction Report 🍇
Historical bunch weights reporting
If you need a reminder of what your historical bunch weights were in past seasons, we have created a brand new Sectormentor historical bunch weights report, to help you pick the right season for this year’s prediction.
Get in touch with us at email@example.com if you have historical bunch weight data that you want us to upload to Sectormentor – we’re very happy to do so! Just make sure it’s clear which of your Sectormentor blocks the bunch weights belong to 🌞
We’d love to hear what you think of these updates. Fo let us know if you have any feedback or questions, or if there’s anything we can do to support.
Example shot of the Historical Bunch Weights Report 🍇