Dirty filters

By ayr February 24, 2011

One of the greatest improvements to food quality that the restaurant brought is filtered water. We used to use straight Boston tap water for everything. Now our coffees, other beverages, and soup stocks are built with filtered water. It’s a beautiful thing.

I got to change the filter the other night at Harvard Square, which I hadn’t done before. We were told the filter change would be every 6 months, and here we are at 3, but we use a lot of water. We use a 2-stage filter. This is the first stage, sediment. That white column is the new filter. The plastic housing was cleaned and re-used. The grey color to the plastic housing is due to the dirty filter that is in there, waiting to be replaced.

The second phase is a chemical filter. They use “activated carbon,” which can be made from a lot of things, but is often made from coconut husks. It has one of the highest surface areas of any material. One gram of this stuff can have over 500 square meters of surface area. That’s totally nuts. It’s because the stuff is so porous, and all of those surface sites are waiting to grab passing chemicals contaminants like Chlorine (which is put in the water by the water authority to kill bacteria).

We’ve made Jose’s happy with the customers we send his way over the years as we don’t sell water on the trucks. It’s been a funny challenge. I don’t want to sell bottled water, largely for environmental reasons, but also because I don’t think people should have to pay for water. But we don’t have room to pack anything on the trucks that we’re not selling. The result: water, which is Au Bon Pain’s largest selling SKU (item), is something we don’t even offer on the trucks.

But at the restaurant we’re able to offer filtered city water for free. It feels really good. We even set up a water carbonator (more on that later), and give carbonated water away for free as well. We take a hit on cups (it costs something like $0.12/ cup), but I can’t figure out a way to charge for that and not water without being annoying, right? So drink up, and enjoy!

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