Sweet potatoes are coming into season now and there is so much that you can do with these fabulous vegetables! They can be fermented into a delicious drink, called Sweet Potato Fly. It is essentially a kvass, which is a staple in some Eastern European countries (traditionally made by fermenting bread, beetroot is another popular kvass ingredient). It is easy to make and definitely worth trying. You can make it with just the sweet potato, sugar and water; however, the other ingredients are what really add the extra dimension.

Sweet Potato Fly
500 g sweet potato (scrubbed or peeled)
1 cup sugar
1/2 tsp nutmeg
1/2 tsp cinnamon
1/2 tsp dried ginger or use fresh
1 whole lemon, use zest plus juice
1 egg shell (I use the shell of a boiled egg)
** you can add 1/4 cup starter culture like live kombucha, water kefir, ginger bug or whey if you like, but it is not strictly necessary – especially in warmer weather.
Filtered water

Grate the sweet potato and put it into a colander a rinse until all the starch is removed (water runs clear).

Add to a large (2.5 L) jar and add all the other ingredients, except water. Mix well and then fill the jar with the filtered water. Secure a piece of cotton cloth or paper towel over the top with an elastic band and leave on bench to ferment.

After about a day, bubbles will form and the grated sweet potato will rise to the top. Give it a stir with a clean spoon, replace cover and leave for another day. Stir twice a day with a clean spoon.

Taste it after the second day to see if it is to your liking, and leave for another day if it is too sweet. When it tastes how you like it, strain off the water and put into an airtight bottle — plastic is probably better for safety. Leave on the bench tightly sealed for another day.

You will notice that the bottle becomes hard with gas build up. Use caution as it can explode if left unchecked for too long! Place into the fridge to chill and slow fermentation. Drink and enjoy!
If you are not used to drinking fermented drinks, take it easy and start with a small glass and build up over time.

The drained sweet potato can be used in a cake or added to any number of savoury soups/slow cooked meals/curries to add bulk and flavour.