Hi Jana, 

Thanks for reaching out about preserving turmeric. Fresh turmeric root will usually keep good quality in the refrigerator for a couple of weeks in a sealed container, but if you have a large quantity you might want some other options to extend the shelf life.

You can dry and powder turmeric at home by peeling it, slicing thinly, and drying in an electric dehydrator set to 135°F until crispy (up to 12 hours). Turn the slices into powder by using a spice grinder, and then store in an airtight container. Turmeric powder will keep good quality for months or even years if stored well.

You can also freeze turmeric root in slices or chunks. Make sure to use moisture- and vapor-proof packaging (freezer bags or tempered glass jars) to reduce the chance of freezer burn. Turmeric kept in this way is best if used within six months.

Storing in oil is another option, but it comes with some food safety risks it's important to know about. A few years back there were some food poisoning cases (botulism) traced back to people storing garlic in oil at room temperature. Bacterial spores are naturally present on our vegetables, and some pathogens start to grow when the fresh vegetables are stored without oxygen at room temperature. Submerging roots in oil is one of the ways you can create those conditions. 

To store turmeric in oil safely, you can slice or shred the root, and submerge in an oil of your choice. Do not leave this mixture at room temperature. You can safely store in in the refrigerator for 4 days, or for longer storage you can fill the mixture into a freezer container and freeze indefinitely. 

You can read more about storing vegetables in oil on our website. The University of Guam also has a more extensive publication on turmeric that includes instructions on drying. 

Thanks for using Ask Extension!

Jared