Biodegradable only good if it's being degraded
Biodegradable packaging is a bit like carbon offsetting - of dubious value if it is only a band aid for our guilt. We actually must be biodegrading the packaging to make the premise work. Guayaki, which imports organic and Fair Trade loose Yerba Maté, the Argentinian tea-like drink, was attempting to improve its product's shelf life freshness. But foil, the common choice, is not very eco-friendly. Guayaki eventually chose old-fashioned cellulose film (which also happens to be biodegradable) that is "metallized" with super thin aluminum film. Thus Guayaki says it has perfected a "carbon-subtracting" packaging - biodegradable, and at the same time, the growing the maté soaks up more CO2 than processing, packaging, and transporting the product. So each 16 oz. pouch of maté is "reducing" CO2 573 grams. TreeHugger asked some detailed questions about the Guayaki maté's true capacity for CO2 soak-up and the bag's ability for breaking down in the backyard pile.
TH: How are the bags made?
Guayaki: The bags are made of 2 layers of cellulose films and are printed using water-based inks. The outside layer of the package is transparent cellulose, and the inside film layer is made of cellulose with one side coated by a vacuum deposited ultra thin layer of aluminum. The outside cellulose layer is reverse printed so that the eco-friendly water-based inks are trapped between the layers; this is so the ink cannot scratch off. The metallized side is also trapped between the layers so that the product inside is only in contact with the transparent cellulose layer. Each 16-oz pack of organic, shade-grown and fairly-traded San Mateo Loose Yerba Mate achieves a subtraction of 573 gm of carbon.
TH: How was the biodegradability of the bags tested - under what conditions and what type of internal heat in the compost pile?
Guayaki: All of the materials that the bags are made of have been tested and meet the requirements of ASTM D 6400 and also Vincotte OK Compost Home. According to Innovia, the OK compost home test is conducted at ambient temperature. Tests have shown that the average total time for complete biodegradation of cellulose film is 80 to 120 days for coated cellulose products.
TH: How did you come up with the 71 grams of carbon for the transport...wouldn't the maté be shipped to so many different locations? Or how did you calculate that?
Guayaki: We used a weighted average distance traveled that is based on each distributor’s zip code and its percentage of Guayaki total sales. An average distance was assumed from distributor to retailer.
TH: Could you also explain about the carbon profile of the mate - why is the tea-processing so relatively carbon-intensive compared to the transport?
Rob Sinclair, of Conscious Brands (www.consciousbrands.com), - the company that conducted the carbon assessment of Guayaki’s supply chain: The greatest journey the yerba mate makes from the rainforest to the consumer is by ocean freight, which has a relatively low per unit distance and mass emissions rate. Tea processing includes two major steps. First it is dried in South America, which is done with biomass, which, although ‘carbon neutral’, does emit some non-CO2 greenhouse gases which are accounted for. The second processing step includes substantial facility electricity use to mill and package the final product. The emissions rate for electricity in the region where Guayaki packages is below the national average, but, nevertheless, the greenhouse gas impact is comparatively large as seen on the label.
TH: How much aluminum (in grams) would come from the package and how much aluminum would need to be in a backyard compost before the compost composition would change enough to worry about?
Guayaki: According to Innovia, which makes the NatureFlex metallized cellulose, the amount of aluminum applied to each bag is less than .02% of the total bag by weight. Each of the new empty Guayaki bags weighs .4 ounces, so the total amount of aluminum contained in each bag to be composted is less than .00008 ounces, and the conversion to grams = less than 0.0023g. In the Earth's crust, aluminum is the most abundant (8.13%) metallic element, and the third most abundant of all elements (after oxygen and silicon). However, because of its strong affinity to oxygen, it is almost never found in the elemental state; instead it is found in oxides or silicates. In the decomposition process for Guayaki bags, the ultra-thin coating of aluminum oxidizes and turns into aluminum oxide which is inert and non toxic. We did some research to find out if there is a regulatory limit for the amount of aluminum allowed in compost that is sold in the marketplace, etc.., and could not find any information to that effect. More specifically, research indicates that aluminum is not one of the metals that the state of California regulates and tests for in their compost regulatory program. Via: Guayaki
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