public double getDensity(String[] ingredients) {
		int sumVolume = 0;
		int sumMass = 0;
		for (String string : ingredients) {
			Pattern p =
					Pattern.compile("(\\d+)\\D+(\\d+)\\D+");
			Matcher matcher = p.matcher(string);
			if (matcher.find()) {
				// <Volume>
				sumVolume += Integer.valueOf(matcher.group(1));
				// <Mass>
				sumMass += Integer.valueOf(matcher.group(2));
			}
		}
		return 1.0 * sumMass / sumVolume;
	}