> 4,000 tons

I did some math out of curiosity to better visualize this amount in my head. If we assume that a typical serving of potatoes in a meal where potatoes are an important part is 200g, then with 4 million kg of potatoes you can make 20 million of such meals (1/4 of Germany's population).

Or ~1600k small sacks of potatoes. About one sack per two people in Berlin, which is probably around roughly one per household.