The art of high-volume winemaking

Set on the northern edge of the Barossa Valley, with 260 ha under vine, Oxford Landing Estate is not small. But by micromanaging 130 two-hectare blocks as separate ecosystems, the grapes are given exactly what they need to achieve optimum flavour, using techniques such as detailed pruning, canopy management and crop thinning.

Winemaking presents challenges of timing and consistency. The grapes need to be harvested at peak ripeness and processed within a critical window of time where the acid and sugar content are at a premium.

Customers get used to a particular label and expect a consistent taste across vintages, but every year the acid level is different and the sugar content is different, as are the aromas and colour of the berries.

The challenge for parent company Yalumba in establishing Oxford Landing was to balance high-volume processing technology with winemaking art.

“The aim for the Oxford Landing winery was an environmentally friendly plant incorporating the latest in winemaking technology, plus a new and unique process stream methodology. The objective was to achieve greater management of the process and the product,” said John Ide, winery operations manager at Yalumba.

The secret, says Ide, is the automated process streams that ensure the grapes are fermented under optimum conditions, given the high-volume throughput. It is particularly critical at all times to control fermentation rate and minimise oxidation, both of which are highly dependent on temperature.

From the moment the skin is broken during harvesting, it’s important to move the product quickly through the crushing stage, chilled and into the controlled environments of the fermentation tanks.

The agility needed to meet the demands of frequently changing production demands is met by process automation solutions from Rockwell Automation.

Virtualisation and visibility

The control and automation system performs sophisticated control of the numerous process streams while at the same allowing the winemakers to exert their influence and apply their experience to achieve the desired result.

Winemakers and operators specify process streams, crushing speeds and fermentation schedules, plus monitor the operational status of the entire plant. The site also allows maintenance operators to keep a close watch on trends using remote access, without having to come to site.

FactoryTalk View SE is a key component of Oxford Landing’s automation system, providing a clear view across entire lines and production processes.

Flexing muscle

At the heart of the system, more than 10 Allen-Bradley ControlLogix programmable automation controllers (PACs) oversee a myriad of drives that control screw feeders, crushers, pumps, presses, agitators and so on, and also encompass enhanced PID control of temperature. “We have introduced a system for automatic dosing of yeasts for ferments which is also controlled by this system,” said Ide.

ControlLogix also controls the advanced refrigeration plant — perhaps the most critical function of all. “The refrigeration plant is our main tool for controlling temperature at all stages of the process,” said Ide, explaining that three ammonia compressors and a pumping system circulate liquid ammonia through the must chillers, ‘rack and return tanks’ and fermentation vessels as required.

The control system works out the required load and directs which should be the lead compressor and what the optimum settings are, based on how much cooling is needed for the required fermentation rates.

Two shades of green

The Oxford Landing site employs a number of strategies to ensure environmentally friendly practices. The efficient refrigeration system has the option of off-peak loading to reduce both electricity costs and power consumption through maximised compressor efficiency. In addition, the hot return ammonia gas heats the water used for washing tanks throughout the plant, plus Oxford Landing has its own complete wastewater recycling plant.

The plant and wastewater facility recently won an Environmental award from the South Australian Wine Industry Association for implementing an innovative crossflow filtration system that minimises waste going to the plant while increasing yield.

“In addition, we are currently utilising our newly installed FactoryTalk EnergyMetrix system to control the maximum kVA demand and email alarms when we are nearing the limit. We are in the stages of using the integrated system to automatically shut down other non-critical motors to reduce demand when we are approaching the limit,” explained Ide.