Recently I volunteered at two different Colorado wineries to give them a hand bottling wine. It was a great experience and one that I learned a lot from.
While I did expect the two different wineries to have different bottling procedures I was struck by just how different they were. On the one hand was a simple, no frills bottling process much like any amateur wine maker does on their own. On the other hand was a more complex process that required some specialized equipment.
Here is a synopsis of each bottling process.
A Simple Bottling Line
At Winery A they employed a simple and straight forward bottling process. The wine was pumped from the tank through a filter with an impeller pump into the bottle filler. The filler had an six bottle capacity.
Empty bottles were taken from their cases and put onto the bottle filler. Once full the bottles were removed and set down where the person running the corker could reach the bottles.
The corker was responsible for ensuring that the bottle was filled to the appropriate level. Not too much and not less than what’s supposed to be in the bottle. Wineries can get into legal trouble if this is off on a consistent basis.
If the bottle was filled to the correct level they inserted it into a mechanical corker. By pressing a pedal on the floor the corker was set in motion. It would push the cork in by force and then load up a cork for the next bottle. The entire operation took only 1 to 2 seconds to complete.
After the corks were inserted the full bottles were placed back into cardboard cases. As the cases filled up they were stacked in a specific way to ensure that they did not fall over when the pallet was moved.
This process is very much like the amateur wine maker’s set up. Instead of a pump often times we’ll use a siphon and we’ll also use a bottle filler that handles one bottle at a time instead of six. Our corkers are also mechanical but not quite as automated.
A More Complex Bottling Line
Winery B’s process was a bit more involved. First the wine was pumped from the tank to the bottle filler using a double diaphragm pump. These pumps offer much more control over the flow rate of the wine and require an air compressor in order to function.
The wine fed into a reservoir on the top of the bottle filler which also had the capacity to fill eight bottles at a time. In addition to wine in the reservoir there was a gas line that delivered nitrogen. The nitrogen exited the gas line below the surface of the wine so there was a constant bubbling noise coming from filler.
With the reservoir cover securely in place the nitrogen served two purposes. Most importantly it protected the wine from oxygen exposure as nitrogen was undoubtedly flowing out of the reservoir. At the same time the bubbling action of the nitrogen in the wine can help degas the wine so if there was any carbon dioxide left in suspension as we were going to bottle the nitrogen would help remove it.
The bottles we were filling were removed from their cases and were placed upside down on a valve. When the bottle was pressed down onto the valve nitrogen was released flushing the bottle of all oxygen. Only then were the bottles placed on the bottle filler.
After the bottles were full they were picked up by the person working the corker. Winery B used a different corker, one that worked on a vacuum system, more on this in a minute.
Because they used the vacuum corker Winery B was able to store the full bottles of wine upside down. This kept the cork submerged but also would allow them to see if any corks were leaking when they came back three days later to label the bottles as leaky corks would leave stains on the cardboard case. This was their standard bottling procedure.
The cases were stacked upside down, as I mentioned, but then they were also numbered. This was a quality control measure put into place to identify which cases could be affected by a bad batch of corks. The owners did say that they had not had this issue yet but had heard from other wine makers that this can really save a winery a lot of headache were it to happen.
Mechanical vs Vacuum Corkers
I’d like to compare the two different corkers used in a bit more detail. I found both machines to be quite fascinating.
Vacuum corkers have a narrow sleeve that is set down on top of the neck of the bottle. On top of this sleeve is the cork that it is going to insert. In the middle of the sleeve is a connection for a vacuum line.
Once the cork is in place and the sleeve is lowered onto the neck of the bottle the vacuum engages and sucks out all the oxygen and any remaining nitrogen. When the vacuum pressure gets low enough the cork is actually suck through the sleeve down into the bottle. If the vacuum pressure is set correctly the cork will stop moving when it is aligned with the top of the bottles neck.
Instead of having to press a pedal as you would with the mechanical corker on the vacuum corker you simply press the bottle into place to initiate the corker. Sensors would be triggered and the machine would do its thing. The entire process from placing the bottle against the sensors to the time it lowers the bottle back down for you to remove it is probably 1 second or less. It is a very fast system.
This corker offered three advantages over the mechanical corker. First, the corker was set in motion only when the bottle was in the correct place. The mechanical corker started moving as soon as the pedal was pressed and it was entirely possible to shatter a bottle if it wasn’t lined up right when you pressed it.
Second the vacuum corker gave the bottle back when it was done. The mechanical corker would quit half way through inserting a cork if you didn’t hold the pedal down long enough. This made it challenging as you had to coordinate three of your four limbs to keep the machine going.
Lastly, and most significantly, the vacuum corker removed oxygen from the head space in the bottle. This allowed the winery to store the filled bottles upside down immediately after inserting the corks. There was no three day waiting period before allowing the wine to come into contact with the cork.
With the bottles resting upside down in the cases it would be clear when they came back several days later to label the bottles which corks were leaky as they would leave wine stains on the cardboard.
So all in all the vacuum corker was faster, more reliable, and left no oxygen in the bottle. In general vacuum corkers are a bit more expensive, however, I can certainly see that it had many clear advantages over its mechanical sibling.
On average we were able to bottle about a case of wine per minute. Sometimes we could go faster than that but that wasn’t sustainable.
While it may not be practical for the amateur wine maker to go out and purchase pumps, bottle fillers with an 8 bottle capacity, and a vacuum corker there are still some things we can learn from these two wineries bottling processes.
First of all, both wineries used new wine bottles as is from the box. Neither felt that there was much chance of spoilage organisms hiding out in a brand new bottle so we did not sanitize any empty bottles. Both had found that clean, empty wine bottles don’t tend to harbor the sorts of micro organisms that spoil wine.
If you’re working with new bottles still sealed in the box you may be able to get away with not sanitizing them. That being said it is still good practice to do so. Each of these wineries was bottling over 100 cases of wine at one time so sanitizing over 1000 bottles wasn’t really an option.
Keep a spray bottle of potassium metabisulfite solution handy. At Winery B we found this to be very helpful when touching up equipment or work surfaces to ensure that they are indeed sanitary.
If you do use natural cork closures it is a good idea to give it time before setting the bottle on its side, however, after the grace period you could invert the bottle entirely to see if you have any leaky corks.
Not all bottle fillers have a way to shut off the flow of wine if they get too full. So if you find yourself looking to purchase a bottle filler keep this in mind. It could overflow if you’re not bottling fast enough. I know from first hand experience!
Lastly, bottling is much more fun with a glass of wine and a few friends. It goes more smoothly, everyone has a good time, and the task just isn’t as daunting this way.
To learn a little bit more about the double diaphragm pump versus the impeller pump check out Winemaker’s Academy Podcast episode 10.