Whisk the yeast & warm water together in a medium bowl, set aside for 5 minutes.
In a large mixing bowl, combine 8 cups of flour with the sugar, make a well.
Whisk milk, oil & eggs into yeast mixture then pour into the flour/sugar bowl. Using your hand, mix the ingredients together, until the dough is smooth. The mixture will be quite sticky. Cover & leave to rise until doubled in size ( 1-1 ½ hours).
Transfer dough onto floured bench, knead the dough, adding flour as you go until the dough begins to have had sufficient flour added that it is less sticky, and more manageable. Then break off 40 chunks of dough to make each doughnut. Knead each dough into a ball & set aside.
Heat oil in a large pot. Test oil with a small piece of dough (should rise & brown lightly within seconds).
To make donuts, pierce a hole in the middle of the dough with your finger, then slightly stretch it out or spin it around your finger to enlarge the hole to about 3cm, then carefully lower the donut into the hot oil, turning the donuts as you go. Fry for about 3 minutes or until golden brown & cooked through. Transfer onto a rack to drain and cool.