What happens after harvest?

A question often left out of discussion, but one of the most important phases in a vineyards annual cycle.

So, what does happen in the vineyards after harvest?

The answer is simple - a lot.

After the bunches has been harvested the vines continues the process of photosynthesis, but instead of transporting the carbohydrates towards the bunches, it gets stored in the root system and the trunk. A grape leaf will only contribute approximately 90 days of its photosynthetic cycle towards growth and berry ripening, where after it will change its trans location from upwards to downwards, in other words towards the roots.

So in basic terms the vine stores food and water for the next season. This is why after harvest fertilizing and irrigation is so important. Having water available is a massive advantage, but here at Darling Cellars we have approximately 95% dryland bush vine. We are completely dependent on the weather. We now wait for the first decent winter rains before we can fertilize, otherwise the fertilizer would be wasted as it can not get flushed into the soil.

When the conditions no longer favour nutrient uptake or the plant is saturated, the chlorophyll in the leaves start to break down and the leaves turn yellow. When leaves turn red it is either due to Leaf Roll ( a virus, but only shows red leaves on Red grape cultivars), or it is Teinturier grapes.

Leaf Roll Virus

A lot of other chemical processes are happening as well, but none that I can explain in a single blog entry. Maybe another time.

Last load of 2011

That's it. Done. Finished! The last load of grapes for 2011, Petit Verdot. Came in brilliantly. Healthy grapes, good pH and acid. Now the heavens just need to open and give us some rain.

It was a dry harvest, but not as bad as I thought. In fact, it was a rather good harvest. Now we can start working towards the 2012 harvest.

Composting

I started making compost in 2009. I use all the grape skins, pips and stems. So basically I recycle the waste product of the wine making process.

In 2009 I only made 100 cubic meters, just an experiment. It went very well, but there were still lots to learn. Last year I made 550 cubic meters. That went even better and I learned some valuable lessons. One of them were that the stems makes handling very difficult. It also causes the compost heaps to dry out too rapidly due to too much aeration.



So the stems are left untouched for at least a year so the the UV can break it apart a bit. This makes it brittle and it manages better the next year. The stems are an important ingredient in the mixture because it helps with the longevity of the product.

This post does NOT relate to static composting, which is a whole different story.

The key factors involved in making good quality compost are moisture, aeration, pH and C:N ratio. The micro organisms (MO) struggle to function at low pH. The grape skins naturally have low pH, and this gets adjusted by adding Calsitic lime to lift the pH to 6.5. They also need Nitrogen as "fuel", so that's why you need to add a food source like chicken manure (or any manure).

The MO also need moisture to function, and obviously air (oxygen). If you don't aerate the heaps they become anaerobic and will start to smell bad. Compost should never smell bad. Bad smell = bad compost.

I try to turn the compost every second day, but it is turned mainly according to the temperature readings. You need the temperature for the first week and a half in the 70 degrees Celsius region. This sterilizes the compost and kills off nasty pathogens and weeds.



After this fermentation phase the temperature comes down to the mid 40's, and will more or less stay in that region. (unless you get a lot of water on the heap, like you can see in the graph where it rained)




The process takes about 10 weeks.

In the cellar

Things are starting to slow down now. We are nearing the end of the 2011 harvest. It was a difficult harvest. Very dry and very hot. But the wines are looking good and as you can see the winemakers are quite optimistic about it.

Here are a few photos of processes in the cellar.

Hydrolic valves - used to open and close channels.

Fermenters

The cellar workers

Hopefully the next post will have some more text in. I am a visual guy, so the photos are satisfying. If there is anything specific you would like to see, drop me an email. Cheers for now