Sunday, November 30, 2008

Secondary Fermentation Continues

At three weeks into the second phase of fermentation, the Riesling wine is beginning ever so slightly to clear. Last weekend I had a scare when I logged into the server and saw that the air temperature in the basement was 52 degrees. The furnace went out the night before and the temperature was in free fall. I made a brief trip up to the Shier and re-started the furnace. I am wondering if poor ventilation and the high level of carbon dioxide was affecting the oil furnace ignition. The thermometers on the carboys were each at 54 degrees. Again, the D47 yeast survives down to 50 degrees. Close call. When I returned this weekend the carboy temperatures were back up to 57 degrees and the wine was still bubbling up.

I measured the SG on a wine sample from the third carboy. It measured 0.999. So far, so good. I will add oak chips to the third carboy in four weeks. If all goes according to plan, I will rack and cold stabilize in five weeks.

I also tried to measure the free SO2 level using a Titret test kit. The experience was a miserable failure. Basically, you have to break off a glass tip on the Titret vial and use a miniature eye dropper to put drops of wine into the vial. It mixes with a basic solution in the vial which turns blue until enough drops of wine oversaturate the mixture and it turns clear. At that point the measurement of the fluid is taken from a graduated marks on the vial which indicates the amount of SO2 in ppm. Unfortunately I couldn't get the dropper to suck any wine into the vial. I ended up crushing the vial with pliers trying to get the wine into it. I have my doubts that such a technique is going to be very accurate because I maintain sterility by spraying anything I dip into the wine with SO2, including test vials.

On another note, I received a $45 bill from the Cornell wine lab. $10 more than I was quoted on the phone. Not only did they let the juice sample sit for a week, provide me with useless test results, but they also sent a larger bill. In case there is any doubt from what I have previously written about using the Cornell wine lab, let me be clear that I will never waste any more time with them.

Wednesday, November 12, 2008

Racking and Winepod F/A

I am sad to report that the temperature sensor on the Winepod stopped working last Thursday. When I checked on the Winepod over the Wine Coach Software, the cooler was on and the temperature read 133F. Since it was clear that the juice was not actually 133F in the Winepod, I turned off the automatic temperature control. The temperature sensor shortly thereafter raised to 150F. It is stuck at 150F. On Sunday, the brix read just under 1.0, so I decided to rack and not take any more chances with the Wine Pod temp control. The actual temperature of the juice was 60F.

After email and phone correspondence with Greg Snell and Fred Hekking of ProVina, it seems most likely that the thermistor has failed. Fred will send out a temporary test thermistor which I will wire into the system to confirm that diagnosis. Considering the cost to ship the WinePod to and from San Jose easily approaches $1000, Fred will probably make the repair in person on his next trip to the east coast. Hopefully the thermistor failure is not a common problem with the Winepod, as a rash of failures could easily burn through ProVina's venture capital. I am fortunate in that primary fermentation was near completion at the time of the failure. When the thermistor improperly registers a high temperature, the automatic temperature controller will keep the cooler on full blast without a break. For the folks making red wine with yeast that is sensitive to low temperatures, this could add the extra cost of grape replacement to ProVina's repair costs.

Alicia and I racked the wine for the first time. The process involves siphoning the new wine down a plastic tube into the three 5 gallon carboys. It looks like murky meta-mucil, but tastes surprisingly good. Alicia and I had a sample glass.

After the wine was transferred to the carboys, I rinsed out the Winepod.

Now the wine sits in the carboys for the next month or two until fermentation stops and the wine clears. I plan to add a few oak chips to one of the carboys for the last week or so before the next racking. I will label the oaked Riesling as premium Riesling and use a different colored bottle top.

Wednesday, November 5, 2008

The Brix Fermentation Curve

The above chart shows brix and temperature over time since the beginning of fermentation.
Perhaps with a little effort I could derive the equation that produces the brix curve. Looks to me like brix will be zero on 11/9/2008, about 21 days total when fermenting at 61F.

Sunday, November 2, 2008

Not Done Yet?

Alicia made a trip up to the Shier on Friday afternoon. When she arrived, the house was ice cold. The thermostat read 45 degrees -- indicating that the furnace was malfunctioning and likely off for the past three days. It gets worse. A 30 foot tree has fallen in the backyard. Luckily it only grazed the trellis on the back of the house. Alicia calls me at work. She goes downstairs. There is the sound of a high pitch squeal. I ask her what that Winepod screen says. Alicia can see the reflection of the lamp in the Winepod display, but there are no numbers. The squeal is unbearable. The Winepod is off and has been off since the power failure on Tuesday morning. Alicia presses the reset button on the battery backup and the squeal stops. She presses it again and the Winepod comes back on. What kind of battery backup leaves you shut down when the power returns? Unbelievable.

The must is 54F and the brix is 6. The yeast can survive down to 50 degrees, but not below 50. Did the temperature drop below 50F in the past three days? I fear all is lost and the yeast is dead. The heater on the Winepod gradually raises the temperature of the must back to 61F. Based on the brix reading, it is apparent that little fermentation has taken place in the last three days. Alicia restarts the furnace and checks inside the Winepod. Good news. The yeast is alive and fizzing.

Alicia picks me up at the train station in Poughkeepsie and we go to have dinner in New Paltz. It is Halloween. All the New Paltz kids are walking the streets in costume.

When we return, the house has warmed into the 60s. The brix has dropped below 5. It is clear now that fermentation continued through the week, albeit at a much slower pace. Primary fermentation will not be complete this weekend and likely not until the middle of next week.

Over the next two days, I use an axe from the garage and a small handsaw to remove the tree. I clear the leaves with a gas blower. I check the brix with the hyrdrometer. It reads 1014. By 9PM on Sunday the brix meter reads 3.37. I plug the Winepod back into the well. It turns out that the battery backup failed because the Winepod uses more than 500VA. I put a thermometer on a stick in front of the camera (as shown above). This will allow me to monitor the temperature in the basement over the internet, which will be important for secondary fermentation.

One more thing. I couldn't resist taking a sip of the wine. With the fizzing carbonation and remaining sugar content, the wine tastes like a mimosa.