Viticulture Week 5 – Come rain or shine…

In Course notes by Classtoglass

After weeks and weeks of delicious sunshine, the rain returned. Come rain or shine, the Viticulture and Winemaking students of Melbourne Poly were out in force, on foot or in tractor.

Top three things I have learnt this week

1. Tractoring in the rain

Soggy tractor

With eyes firmly on our weather apps and the forecast thunderstorms, we were half expecting (hoping) that our tractor lesson would be cancelled this week. Let’s face it, none of us fancied getting caught out in a a paddock in a giant lightning rod.

The thunder held off, but unfortunately the same was not true for the rain. It hammered down – almost biblical like. Deep down I knew that tractors must be able to work in the rain. If not the the whole agriculture industry in the UK, for example, would just collapse. I didn’t realise that it would have such an effect on how you drive them.


Massive wheels and deep treads do help when manoeuvring up steep muddy banks. However, this week the 4WD and differential peddle were very much needed. That sinking feeling that you get when your tractor loses wheel traction whilst reversing uphill… priceless. Just enough time to flick on the 4WD. But then, one wheel loses traction. Heel on the diff peddle to ensure that both wheels have the same power. Terrifying.

I made it! Twice. Big adrenaline rush.

Enough said.

2. Sugar and alcohol


Two beautiful things. This week in Wine Chemistry I learnt how to test wine for the concentration of sugars and the percentage of alcohol.

Yeast ferment sugar to alcohol, so theoretically your finished wine should contain very low concentrations of sugar and 10-16% alcohol. In practice ‘dry’ wines can have up to 1g/L glucose and fructose sugars. To test for them you use an enzyme analysis kit. Testing our Teachers Pet Shiraz showed me that it contained 0.89 g/L sugar – it is therefore ‘dry.’ Yay!  I next tested a commercial wine being processed in the university winery.  It was also dry – so we knew that we could proceed with pressing. All eight tonnes of it!

8T Press

Working in the university winery is amazing and tough. Pumping eight tonnes of Heathcote Shiraz into a press is a huge undertaking, and resulted in some of the most beautiful ‘water’falls I have ever seen!

Alcohol concentration can be measured in a couple of ways, but this week I was doing it with an Ebulliometer. Even the word Ebulliometer sounds antiquated – the piece of apparatus in question looks as oldy-worldy as it sounds. A sample of wine is heated to boiling with an ethanol burner. The stainless steel contraption features a kind of reflux column and a mercury thermometer that indicates alcohol percentage. After calibrating it first with water and then four standard ethanol solutions, I tested our Teachers Pet Shiraz, which is around 13.5% alcohol. Perfect!

3. The Shiraz rose challenge

Growling Frog Vineyard

We were all back in Yan Yean on Friday for Winemaking 1. Assembled at 8am to pick grapes for our class wine, we hit the misty vines. The nets were still on this patch of Shiraz grapes, which made the task a little tougher than envisaged, as for many of us this was our first picking session. Without nets, kangaroos and birds have a field day with the grapes. The ‘decoy’ vines that hadn’t been netted had been decimated.

3 bins and some buckets

In pairs we managed to pick three bins and lots of buckets of grapes. Probably lots more too – but I had forgotten my toast and was starving. The grapes varied significantly in their flavour and acidity, and we were all keen to get them back to uni and test their potential. It is no secret that as a collective we were less than enthusiastic about having to produce a Shiraz rosé each for our assessment. These grapes will be our main tool for this.

Unfortunately we remain underwhelmed. The Baume of these grapes is a mere 9 – meaning they have a low sugar content. Usually you would expect a high acid concentration in contrast, but no. The pH is 3.72 – very high. So not much sugar (to turn to alcohol) and not much acid to balance the flavours. This will be a challenge indeed. I have lots of ideas – but a bit of a miracle would would be appreciated right now. Could I add some sugar? No – apparently that is illegal in Australia – huff!

Free running juice


We had fun as a collective squishing, pressing and testing the grapes though. They were pressed as whole bunches straight away to reduce skin contact and keep the colour low. As well as the rose we are also making a class Shiraz, which went through the crusher de-stemmer in preparation for maceration.

Balls in the air

So just as we got our bathroom back from the Teachers Pet Shiraz, it is once again host to a ferment, and this is just the start… I have a few exciting, experimental and maybe a little risky ideas to pep up this flabby juice in order to make a stunning wine. Articles coming soon, but let’s just say that I am calling in the Pinot cavalry and considering sparkling options. Indeed, many balls in the air…

This week… I have a week off the tractor to attend a Viticulture lecture, another shift in the winery and wine making continues on Friday. Another day another glass!

Thank you for reading.