Keep your biodiesel in an sealed airtight drum, as full as practical. This may mean decanting it into smaller containers. The less air in the container, the less oxidation of the biodiesel.
Keep it in a dark place if the containers are not light excluding (steel drums are fine), and keep it out of the heat.
Biodiesel can keep for more than 12 months under these conditions.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.