Harvester drivers can learn a thing or too, as well. Both in viticulture (plant production) and viniculture (wine production).
My foray into the Australian harvesting season over the last two years, in an area contaminated with phelloxera, has opened my eyes to a far greater involvement by winemaker and vineyard owner in the whole process.
For red varieties, the quality standard for sparkling base traditionally meant clean samples & most definitely reduced juice collection, as opposed to fermentation requirements – opinion is becoming divided – where cleanliness is much more of a requirement. But many winemakers and growers were completely unawares that until Pellenc harvesters arrived, juice collection was non-existent, and the “totally clean sample” myth was quite costly.
The very fact that the Pellenc harvester was the first harvester on the market to RETAIN all the grape juice had slipped in under the radar, and as winemakers demands took precedent without knowing, totally clean sample requirements meant the suction fans had removed up to 200-300 litres of juice from a 1/2 tonne bin of fruit.
Australians are more interested in the quality of the pick (i.e. whether there is MOG present or not), rather than whether the operator had retained all the juice.
So, from the “we need to bite the bullet & bash it off” on the first night (with sporadic rain fall), to “something is wrong with the [kiwi] driver” sentiment after the fact on the following night, I learnt the hard way that we were no longer picking sparkling, and I should have made greater effort to remove all the MOG (and in so doing , ensuring that the winemaker understood that we would be sacrificing some juice).
Of course, as soon as you tell them that, the horror of the realisation of what that meant very quickly sunk in, and opinions changed.
Just have a look at the Operators Handbook or other productions by Pellenc Australia for example, which includes page after page of binned fruit samples – with very little presence of juice. Growers and winemakers in New Zealand would cry foul, if I delivered a similar sample.
With these thoughts in mind, amplitude is the setting which splits the skins the most and should be reduced to mitigate this. Frequency needs to be proportionally higher then your ground speed, and acceleration is useful here. Pinot (114, 115, 777) can require lower speeds/higher amplitudes along with Merlot, whereas Pinot (5, 23) and Cabernet are much easier to remove off the vine. Earlier the pick, the more difficult, as is partially ripe bunches (where smaller developing berries are left behind).
Reducing the Active Length of the shaker bars, literally means that when set between the minimum of 50% to the maximum of 150% of the total picking length, the shaker bars return from the post settings (if sensed) back to the picking settings – at the percentage of the length you’ve chosen.
But it depends whether you have increased OR decreased settings around the post, and what your attempts are around the post, – whether you reduce or extend the picking length…
If you have an easy pick (fruit falling off, not MOG, etc.) then quite often the SMART settings will be quite low (or should be). That being the case, harvesting around wooden posts may still be difficult, so it would be reasonable to increase at least the frequency at this time. Because you are shaking more than necessary as between posts at this point, shortening the active distance wouldn’t achieve anything, as you’ve chosen to shake more to remove more fruit around the post. Keeping the active distance longer than 100% would ensure increased shaking after the post, and increase fruit harvested.
But if you have a difficult pick (early season, unripe, or simply require full acceleration/frequency SMART settings) then a decision could be made to reduce or lighten the shaking around posts (to mitigate breakages – as you already have high SMART parameters). By the time you are coming to the end of the active length of the shaker bars, at some point you need revert back to the vine panel settings. To maintain post integrity, set active distance to greater-than 100% (typically to 110%).
Alternatively, a setting of 90% under these conditions would ensure a greater chance of fruit removal after the post, and yet reduce the effects on the post. In practice though, noticing a difference can be subjective, and my experience shows little effect either way with ground speeds above 5.5km/hr.
Shaker bars are expensive, so they need to be looked after. In the Australian summer, temperatures become so high that bar (including the post sensor rod) can lose its shape completely unexpectantly and very quickly. However, as most harvests are conducted overnight, this isn’t too much of a problem, until harvests drag on to mid-morning…
Bolting in a new shaker bar should always be the option, so new rubber axles work in pairs, and straps should always be used when the head is not in use, to restrain their flex and maintain their shape.
Just this 2014/2015 summer in New Zealand, we had considerable difficulty with shaker rods losing their shape, and its no coincidence that we have had one of the hottest summers (and driest) for a considerable time (consistently in the low-to-mid 30’s).
Remember, when bolting up new shaker rods, fit both rubber axles in their housings before you start bolting them up, and make sure you don’t twist the rubber isolators as you are doing so!!