Dear Wine Wizard,
I just came across an old grape press hardly used (from the 1950 era I think). I have two questions: Firstly, what would be a good way to clean and sanitize the wood slats or even the whole press before I put it to use? A fellow winemaker suggested a power washer or a steamer. Secondly, the original owner put copper on the bottom where the juice flows into and then out of the chute to the pail. Will the copper cause an off-flavor to the wine for the short time it comes into contact with the juice?
Wine Wizard Replies: The Wine Wiz would first examine the press (especially the pressure-bearing bits, like the wooden side slats, the floor and any metal joiners) for wear and tear to make sure that, being so old, it truly is up to the task! Old equipment can be fun to look at as well as use but sometimes the old parts are just, well, old. Wood rots, metal rusts and sometimes parts fall off or are lost . . . it’s no fun to load up a ton press with fermented must just to find that the little screw thingy that holds the pneumatic handle on is missing!
So if you’ve examined it and all looks good to go, I do first recommend a chemical-free go-over with a pressure-washer or steam cleaner. It’s a great way to blast off stubborn layers of dirt, old grape matter, and any other kind of random ick. I love pressure washers. Using them to clean cellar floors, tanks or most anything for that matter is so satisfying, seeing clean strips of concrete emerge from under layers of floor gunk . . . but I digress.
Once things are clean to your satisfaction using a pressure-washer, it’s time to get into the nooks and crannies with an old toothbrush or other similar device. Make sure you really get into the cracks and crevices to get any material out and to rinse well with water afterwards. If you have stubborn soil, tartrate crystals or other schmutz still adhering to the press, you could certainly use a strong soda ash and water solution to help dissolve it. Just follow with a citric acid and water rinse, followed by a fresh water rinse, before allowing to dry for storage. Be careful to keep your freshly-clean press in a dry, cool and preferably shaded place as wood molds easily . . . but also gets bleached in the sun too!
As far as the copper spout goes, I wouldn’t worry too much about it as your wine will be passing over it quickly and it’s unlikely to add high amounts of copper to your wine. As an aside, copper fittings were (and in some cases still are) used in winemaking as a way of treating wine for “reductive” or rotten-egg aromas (hydrogen sulfide). The copper reacts with the stinky sulfur compounds and causes them to lose most of their disagreeable smell and fall out of solution. I’ve sometimes used a copper wire screen in my pump over tank when I’ve had a stinky fermentation to great success. A general guideline for avoiding over-leaching copper (which can be toxic to humans at high levels) into your wine is to prevent your wine from being in contact with any copper fittings for more than an hour (especially if you are working with a highly acidic variety). It's not a good idea, say, to let your pressed grapes drain slowly overnight, as some thrifty winemakers I know do to squeeze out every last drop. If having a copper spout at the bottom of the press worries you, feel free to change it out or modify it if possible. Happy pressing!