Column burps

[turbo yeast]

Hi folks,
Just finished with building my first destillation column (see picture). The cupper column is approx 100 cm in length and has a diameter of 35 mm. The condenser is approx 75 cm in length and has a diameter of 28 mm and an internal pipe of 15 mm. However, I am experiencing a problem and I don't know how to solve it. When I fill the pan 2/3 with e.g. old wine to destill the alcohol, after 10 min the temperature quickly increases to 78-79 degrees celcius. At that stage drops of very pure alcohol are produced (90% v/v). Subsequently, the temperature slowly increases to 82.5 degrees celcius...
At that stage the column burps a 100 mL (or so) hot aquous mixure with a low alcohol content, basically ruining my destillation.
I have some theories, but first don't know if they are correct and second don't know how to solve them.
At this moment I am using a heatplate which does not provide very constant heat. My most promising theory is that at a burst of the heatplate, the mixture inside the pan instantly heats up and a burst of alcoholvapour rises up and hits the condensor. At that stage the alcoholvapour colapses and creates a vacuum, "pulling" the aquous mixture up in the condensor, thus creating a burp....
Maybe this just nonsense...
Let me know your theories and please some suggestions to solve this...
Thanks a lot!
Cheers, M