Sunday, May 5, 2013

Cold Stabilization


The 2012 Riesling has been fermenting and clearing for six months.  To lower the total acidity (tartaric) a bit and stabilize the wine, I need to ideally drop the temperature of the wine to 32 degrees for two weeks.  There are a few ways this can be done.  The first, a large freezer room, is out of the question for my small winery.  The second option is to place a cooling line in the tanks that runs also through a chiller unit.  Eventually I may build a chiller coil setup, but it would require modification to my tank lids.  The chiller units and coils are also somewhat expensive, with the unit running $1500 to $4500 and the coils another $500 to $1000.  The third option that small time winemakers sometimes employ is to put the tank in an ice bath.  I decided to go with the third option.

My tanks are large, four feet tall and 24 inches in diameter.  More importantly, when full, they weigh around 750 pounds.  Lowering one of these tanks into a larger drum is not an option.  I can only move the tanks on my fork-lift stacker.  The tanks must always remain on the fork-liftable pallets, which increases the tank base footprint to 24 inches by 36 inches. 

My solution was to use a large plastic tarp.  I rolled the tank and pallet over the tarp before pulling back the fork-lift and raising the tarp around the tank with a clothes line cord. I bought a few bags of ice to add to the tarp.  But I needed to keep it cool for 2 weeks.  And working my job as a lawyer in NYC didn't allow me two weeks to stand by dumping ice into a tarp all day long.  So I needed an ice maker.  Standalone ice makers range in price from $150 to a few thousand dollars.  I needed one that would allow the ice to fall directly into my tarp, so that meant a relatively small unit that I could mount on the wall or ceiling.  Also, ice makers must be kept upright or they stop working very quickly.  For example, I could not use an ice maker in which the ice is held in a bucket under a top-loading door.  The ice maker needed a side pull-out tray, which I could modify into ice cube ramp.

I found this SPT Sunpentown Ice Maker on Home Depot's website for $183.   While most reviews were negative, the unit had a slide out tray.  The ice maker holds water in a lower compartment that the user must constantly refill to make multiple trays of ice.  But since I was not going to be around to add water, I needed a larger reservoir and pump to keep the ice flowing. 

I'm not a fish owner, but it turns out that some aquariums have top-off pumps with float switches.  I found the above Fins, Furs & Feathers Inc. Ultralife Floatswitch on MarineDepot.com.  After removing the ice tray from the SPT ice maker and adding my plastic ice ramp, I installed this float switch inside on the left side of the water compartment.  I connected a Marineland Maxijet pump to the float switch (another aquarium find).  I filled my double-wide laundry basin and placed the pump at the bottom.  The water pump adds water and the ice maker makes ice cubes which it dumps over the tank.  The extra ice and ice water fall off the tank into the surrounding tarp.  

Not a pretty picture, but the ice bath appears to be working.  The tank is icy cold.  I'll have to wait to see how much tartaric precipitates.