Add sugar into the saucepan, fill with water, bring to medium heat, and keep stirring until dissolved. Avoid boiling.
Lower the heat, add powdered ginger, tartaric acid, and cream of tartar into the liquid, and simmer for 10 minutes. Stir gently once in a while.
Turn off the heat once the mixture turns golden, and let it cool.
Transfer the mixture to the plastic bottle.
Dice the pineapples.
Put diced pineapple into the bottle, cover it with a lid, and store it in the fridge for two days.
Open the lid every twelve hours to allow the gas to escape. On the last day, strain the ginger beer into a glass. Add a squeeze of lemon and ice, and enjoy.
