permeate

[Beerclouds]

because all the impurities are pulled out of the sap, including minerals etc. is there any truth that permeate has a shelf life of approx a week?

[DrTimPerkins]

There can be some passage of sugar through some membranes, as well as some passage of minerals. Shelf life will very depending upon the membrane properties and operating conditions. Because of that, growth rates of microbes will be low, but not zero. Permeate should last at least a week unless it gets really hot, and will often last several weeks or even months if stored properly.