Every June while I was growing up, I used to make sliced strawberry jam with my mum. She was a working woman, so it was a process we split into two parts: in the evening, washing and prepping the berries; early the next morning, cooking the jam and sealing the jars. It was the best jam ever.
It still is! I seal my jars in a water-bath now, rather then using messy (and leaky) paraffin. Sometimes I use the same evening/next morning plan, or sometimes I prep in the morning and cook/seal that same evening. In either case, the process is still the same, starting with perfect berries at the peak of freshness.
It’s not a difficult process, and not even that time-consuming. Make jam in small batches – I never make a batch larger than 4 quarts fruit, because the quicker jam cooks, the fresher it tastes, and a large batch takes much, much longer. Besides, I have a small family, so why would I want to make an industrial-sized batch of jam?