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Hamish Elmslie with the Wine Grenade


Grapegrower & Winemaker Editor, Nathan Gogoll, spoke to one of the founders of the Wine Grenade about how this device has introduced a more flexible approach to micro-oxygenation and wine maturation.

The Wine Grenade will not deliver “fire and fury” like your winery has never seen before, but it might change the approach to maturation of wines which otherwise won’t be spending time in barrel.

“A substantial amount of wine produced today never gets to see the inside of a barrel, yet winemakers still want to put the best possible expression of their wines in front of their customers, and oxygen plays a key role in this,” said Hamish Elmslie, one of the Wine Grenade founders.

“We identified that winemakers see a combination of low-rate micro-ox and oak alternatives as the best way to replicate their barrel programs.”

The development started in 2014 when the five company founders were exploring the viability of IP developed by New Zealand’s Plant & Food Research.

“The five Wine Grenade founders took the IP outside of its existing use, which was releasing ethylene for bananas in transit. We suspected there were other opportunities for the application and the one that really stuck out was the controlled release of oxygen to mature wine. When we started to drill down into the process and look at the advantages, we saw some common issues.

“After a series of in-depth market validation interviews, we realised that a number of common shortcomings of micro-oxygenation devices were preventing the process from being more widely adopted by the industry.”

The first winery trials took place at Sacred Hill in 2015, and we began exporting to the USA in 2016.

“The Wine Grenade reproduces the oxygenation levels offered by oak maturation and delivers it to wines that, for commercial reasons, would never see the inside of a barrel.”


How does it work?

The Wine Grenade is a portable device that sits atop a tank and diffuses oxygen into wine through a semi-permeable food-grade membrane.

“We have observed much more effective integration between the oxygen and the wine because of that molecular diffusion process, and our Active Float System means the entire tank receives a more consistent dispersion of oxygen,” Elmslie said.

It differs from other, traditional micro-oxygenation systems which bubble oxygen into tanks through a single porous sinter at the bottom, and offer less flexibility around the size and shapes of tanks available for the winery to use.

“A lot of research has gone into understanding what happens with oxygen when it is diffused through a permeable membrane versus a porous sinter and the effect that has on oak integration, mouthfeel, etc.,” Elmslie said. “The trend among winemakers is toward the subtle use of oxygen over longer periods of time, in order to recreate a barrel program, or to keep wine fresh while under ullage, or to open it up prior to bottling.

“The oxygenation rate is still determined by winemakers and is adjusted online. The devices can be viewed and ultimately controlled remotely from anywhere in the world.”

The first trials were undertaken in 2015 at Sacred Hill Wines in Hawke’s Bay, where the Wine Grenade was compared to the existing Micro-oxygenation technology on site.

“Initially we targeted heavy reds like Merlot and Cabernet Sauvignon but we’re now seeing positive results with different wine varietals including Chardonnay, Pinot Noir, Syrah and Malbec,” Elmslie said.

With Sacred Hill’s support, the first trial was carried out across two 33,000L parcels of wine (Pinot Noir and Merlot) each split evenly across three tanks.

“We were able to do identical trials across the two wines, which included a tasting each week. At every tasting the Wine Grenade sample was the preferred wine.”

Sacred Hill went on to buy the system.

The Wine Grenade is about the size of a lunchbox


Elmslie said the main advantages of the Wine Grenade system are its “ease of use, low upfront cost, and the ability to leverage data from the connected device”.

“Cost is important because we want the technology to be affordable for wineries of all sizes, not just those at the larger end of the scale. Simplicity has been built into the unit from the start – from installation to operation, and portability. Even the ordering of additional oxygen will be a painless process. Sensors and data recording capabilities allow critical information to be sent back to the winemaker.

“Winemakers were telling us about the high upfront cost associated with existing systems. They didn’t like that installation required intensive infrastructure upgrades at wineries, and they generally didn’t like having oxygen lines run all over the cellar. The systems just weren’t economic for smaller operations, and there was a mixed perception within the market as to their effectiveness.

“The unit is the size of a lunchbox, it’s very, very portable,” Elmslie said. “It’s battery powered and the battery life gives you two-and-a-half month’s power from an overnight recharge.”

The Wine Grenade system costs are similar to the costs of a new barrel, it requires less space than large hose systems, and doesn’t need any ongoing cleaning or maintenance.

“Portability and connectivity has been a game changer for winemakers in terms of labour costs, because they can install rapidly and flawlessly their unit, and control remotely their addition of oxygen. Having the unit connected to the wifi network and through an app on your phone just makes it easier to use,” Elmslie said.

What’s required:

  • One US$600 unit is required per tank
  • Two lengths of membrane per tanks (one metre in length for each metre of tank height)
  • Oxygen cartridges (as required to deliver the required dose)
  • Everything else is included with the unit.

When the unit is moved to a different tank (or the next vintage of wine) replacement membranes are required for sanitisation requirements as well as new oxygen cartridges.

“We didn’t want a winery to have to go out and buy a new tank to handle the system,” Elmslie said.

The Wine Grenade system doesn’t require a minimum tank height, like other bubble diffusion systems.

The winemaker feeds the specifics into the system (tank size, length of membrane and desired time of the process) and the device does the programming – providing live data updates every 15 minutes.

“There is actually a huge amount of data that is picked up, it all gets stored in the ‘cloud’ and then is made available to the winery.”

According to the numbers from Wine Grenade, a typical oak barrel delivers a controlled rate of 2mg/L of oxygen per month. The typical use of the Wine Grenade so far has been 0.5mg/L per month in ongoing maturation programs and 2mg/L per month in post-malo settings. There have been experiments at up to 50mg/L per month, however that level would only be suited to very small tanks.

“It comes down to a couple of things – the winemaker’s experience with micro-oxygenation and the variety of wine involved,” Elmslie said. “Starting at 2mg/L per month gives you a low risk, because you have the confidence the rate matches a barrel, and it gives the winemaker the ability to monitor the progress by regularly tasting the wine. The monitoring done by the unit and the data it collects also provides support to the winemaker.”

The device was delivered to a pair of Australian wineries at the start of 2017, after the winemakers reached out proactively. Each winery purchased two units and have recently ordered two more.

While not identified as an initial benefit, the science behind the system suggests it could potentially be used to speed up the maturation process.

“The Wine Grenade reproduces the oxygenation levels offered by oak maturation and delivers it to wines that, for commercial reasons, would never see the inside of a barrel.”