There are a few things that can result in runny chia pudding... not waiting long enough for chia seeds to soak is a big one. Chia pudding should chill in the fridge a minimum of 3 hours before eating. Chia seeds are like natural thickeners – once you add them to a liquid, they will start to form an outer coating. But the longer they sit, the thicker pudding you'll get. So it’s best to make your chia pudding in the evening and then let them chill overnight.