I remember seeing a thread about this several months ago, but alas do not have access to this forum’s search function. I don’t remember if there was a definitive answer to this question either. To clear up any possible confusion, I’m referring to copycat items next to name brand items, often with the store logo emblazened on the side. From my experience most knock-offs have slightly lower quality than the actual items. What is the difference? Are cheaper ingredients used? If so, is that the only difference, or are they manufactured differently?
It depends. The only real difference is that the store owns the “brand” and the specification. Therefore they can switch suppliers our have several at the same time. There is no real reason why it should be any worse, although many stores deliberately target a lower price range. This can mean cheaper ingredients, higher tolerances, simpler packaging etc. Sometimes it is just economies of scale. Big chains that focus on store brands can often sell very large quantities (e.g. here the second largest coffee brand is a store brand) and negotiate with their suppliers as a single, extremely important client. Many store brands do very well in independent tests, but it seems to depend on the overall strategy of the chain.
Most store brands that I’ve used seem to pe equal to their name brand counterparts. The only exception is soda. Most store brands can reproduce the flaor of all the sodas except “regular” soda and grape. Those are hit and miss.
Some store brands come off the exact same factory lines as the national brands, and in other cases the national brands (canned tomatoes and mayonnaise come to mind) have a noticably higher quality than the generic store brands. It varies according to the item.
This may be the thread the OP was thinking of.
I usually buy generic items when I can, and it’s fine to live on for a while but I do think they’re definitely lower in quality. The bread is flimsier, the tomato sauce doesn’t have quite the same bite, the cheap toilet paper doesn’t go quite the same distance as the thick stuff, and the paper towels don’t soak up as much liquid. But I keep buying them because I do save a few bucks, though in the end I go through more TP/paper towels for the same job so items like that more than likely even out in price.