If you want bottles of uniform specification, then new is best, especially if you want them to be of a decent thickness, then new is the way to go. However, most people use recycled bottles.
The best piece of advice about bottles us to avoid multi-pack 330ml and 275ml bottles. They're made of the thinnest glass possible and are likely to break. In fact, unless you're bottling a strong beer or a style that traditionally is packaged in a small bottle, avoid anything under 500ml as a lot of people find bottling a chore.
I use recycled bottles from bought beers but having dropped an (empty) Pedigree bottle from a height of a few inches and seen it shatter into hundreds of shards of very thin glass any of those bottles are now consigned to the recyc bin immediately following the consumption of their original contents!
I can't speak for Aldi and Lidl as I rarely use them as other supermarkets are closer, but Bank's beers are 89p each at Tesco and are pretty good in terms of thickness.
If anyone offers you any of the OLD Magners bottles, bite their hand off as they hold a pint and are nice and thick. The same goes for Grolsch bottles (ask for crates too. If you're unsure about the Grolsch bottles, older ones have rub marks on the outside from reuse. Don't bother with used ones as they're really thin.
Some other advice:
- Inspect every bottle every time you use it for cleanliness and cracks. If your bottle is infected or has a hairline crack, you could end up with bottles that explode if knocked
- Avoid any bottles that have ridges in them. This is an ideal place for bacteria to hide. I've stopped using some old Bulmers bottles as they seemed to be infected. The same might also be true of logos, patterns, writing etc moulded into the bottles
- Buy a bottle brush
- Save the cap and when empty, push the cap back on to stop the bottles getting dirty while in storage (use new caps every time you bottle though)
- Invest in no-rinse sanitiser. You'd be surprised at how having to sanitise and rinse 40 bottles makes you want to give up brewing
- Sanitise you caps. Not only for the obvious reason, but many caps these days are 'oxygen scavenging' and require wetting for activation
- Pay attention to priming. If you over prime, you'll end up with bottles that explode if knocked.
Unfortunately, I don't think any commerical beer is bottled in strong, returnable bottles, so you have to be very sure you know the beer has finished fermenting before bottling and that you don't overprime. The fact a bottle once contained beer is not enough. The large breweries use the thinnest glass possible to save money as they know exactly how much pressure they need to hold as they force carbonate. Many homebrewers don't.
