Spore syringe storage — actual longevity data, not guesses

Refrigeration (35-40 degrees F) is the single most important variable. Cold slows bacterial growth and spore metabolism. Properly prepared sterile syringes in the fridge routinely remain viable 12-18 months. I've used 2-year-old refrigerated syringes successfully, though germination rates do drop over time. Room temperature dramatically accelerates degradation — 6 months at room temp is optimistic for a non-sterile vendor syringe.

What kills syringes faster than anything: contamination at time of production (visible as cloudiness or smell), temperature fluctuation, freezing (ruptures spores), and light. Keep them capped, refrigerated, away from light. Check the solution: should be clear to slightly cloudy from spore material, no green/black/pink coloration. If in doubt, streak on agar before committing grain jars.

Longer storage option: print your own spore prints. Stored properly (paper in foil, in a sealed container with desiccant in the freezer), prints last years — 5+ years with good technique. Then you hydrate to make your own syringes when needed. More work upfront, much longer shelf life.