My trip down memory lane:
My maternal grandfather was a cook in SF most of his adult life (immigrated from Greece) but at one point he partnered with an Irish couple from the neighborhood and they opened a coffee roasting and packing business that was located in the "coffee district" on Third street. This 'hood was HQ for Hills Bros., Folgers and MJB (which was closest to my PahPooh's shop and eventually bought them out). But although that shop is still present it's now a small restaurant and has a pretty good beer selection...but I digress.
His job was roasting beans and keeping that machinery working, also making calls on cafes and restaurants to drum up sales.
He was a diehard believer in the "vacuum" method of drip coffee, which I never adopted but used to watch with fascination when he made the stuff at home...it was like magic to a kid!
I don't know if he always used vacuum makers when he cooked at cafes (breakfast and lunch shifts) but after he left the coffee biz he was friendly with Farmer's Bros (might be still in business) so had all kinds of merch from that outfit. He believed the secret to a successful Breakfast cafe trade was good fresh coffee and as often as not you give it away: any cop, fireman or trades person who stopped in got a free "bottomless" cup every day.