There is, however, a certain trade-off. The pretty and interesting bottles that you can find are, in general, not as consistently made as more standard bottles. Small irregularities in the roundness of the neck can prevent you from getting a good seal when you cork the bottles, and the wide varieties of neck size you get in the first place can make fitting your corks a hard task indeed. That said, with a little care and hard work, I still find these bottles worth using in some circumstances.
So the first question is: where might one find these bottles? In the beginning, there was Pier 1. Actually, there still is Pier 1, but I don't live right up the street from one any more. But back then, in the early days, I bought all my bottles, and most of my glassware, from the Pier 1 on Beacon Street in Brookline. They may not be the cheapest, but they had by far the best selection of exotic bottles and odd-sized mason jars of anywhere I looked. And they were right up the street.
Truth be told, the very first bottles I used were the old 16 ounce CocaCola® glass bottles. These were the short, stout bottles, not the signature fluted bottles people recognize. I stripped off the labels, and kept the plastic twist-off caps. They held my first few failures admirably, but it was immediately obvious to me that I couldn't carry my liqueurs around in such sad looking containers. I might as well keep them in the mason jars - then at least I'd get the comedic benefit of looking like a real moonshiner.
So I went off in search of glassware. At Pier 1, I found some wonderful-looking cobalt-blue bottles imported from Spain. These were actually part of a wider family which, then, included very-pale, almost clear green, and deep, forest-green glass. The bottles were all molded from the same patterns: 3 cup square (far left), 1 quart tall and round (near left), 2 1/2 cup round with grape-leaf decoration (near right), and 2 1/2 cup triangular (far right). They all cost between $4.00 and $7.00, which, although it made them the most expensive part of my liqueurs, was easily affordable. Well, affordable for some definition of the word. I've easily spent thousands of dollars on glassware in the past seven years.
Since I originally found these bottles at Pier 1 (and made good friends with one of the managers there), I've found them cropping up most anywhere. Almost every department store with a housewares section has some offering of fancy bottles, and places that specialize in kitchenwares are full of them. Even craft stores have them. Some stores have varieties that can't be found elsewhere (Crate and Barrel, for instance, has a very small number of designs, but it's the only place you can get those), and I've found it's always worth investigating whatever store I'm in. Whether or not I'm in a buying mood that day, it's worth knowing what oddball designs are coming around.
And oddball designs abound. I have bottles shaped like bunches of grapes, fish, and even the Mayflower (a 17th century sailing ship important to American history). Even the standard bottles are getting spruced up now, with many finding themselves painted in festive patterns, or molded with various designs inlaid in the glass. There is probably a bottle design for every taste, which of course means that most of them won't appeal to any individual person, but the variety is both fascinating and entertaining. With so many to choose from, you might consider selecting a particular bottle design for each liqueur you make, making them distinct and recognizable.
Something you should always have somewhere in your mind when buying bottles is variety of size. Thankfully, the selections of unusual bottles at every store I go to usually has many different sizes as well as shapes. Many full-size bottles have miniature (often half- or third-size) counterparts, and there is an endless variety of small, one- or two-ounce bottles. Especially when giving the bottles as gifts, you might consider using such a pretty, little sample bottle instead of the full quart.
When I've had a fair variety of good liqueurs available, I have been known to give a half a dozen sample bottles to a friend for some convenient holiday. Many people appreciate the opportunity to try several flavors without feeling obligated to drink a gallon of alcohol or more. You can also use the half-sized bottles to give your liqueurs to people who do not drink much, so that they won't have a large bottle staring forlornly down at them from their shelf for months on end. And as an added bonus, smaller bottles give you a way to avoid having to waste liqueurs at the end of a batch. Half-filling a large bottle is, I've found, a sure way to have the contents go bad. If I find myself stuck with extra liqueur that isn't enough to fill a bottle, I might be tempted to throw it out, since it's just going to go to waste anyway. But samples give you a good way to use nearly every last drop of your creations.
I have found one major problem with a lot of glassware, though. As the popularity of colored glass has increased, so has the pressure to bring down prices, at least at the wholesale level. This has resulted in some serious cheapening of materials and design. Mostly, this is just cosmetic, with bottles having lists to one side, embedded grains of sand, or other obvious flaws. Usually these defects aren't serious enough to cause the bottle to fail, but I do check more carefully than I did in 1991. But one serious thing is that many bottles are just white or pale-green glass which has been painted the desired color. I haven't heard that the paint is toxic, and I expect it isn't, but the paint definitely leaches out into the liqueur stored within it. At the very least, it smells and tastes terrible. I won't use them.
It's getting hard to tell the painted glass from the real dyed glass, though. I first discovered the painting when I was cleaning a neat little light-purple bottle I had just been given. I poured boiling water into it, and was hit in the face with a really foul odor. I put it aside and moved on to other bottles, and didn't return to it until the next batch. I then looked a lot closer at it, brought my girlfriend in to consult, and we decided it had to be that the glass was painted. We could see by the differences in color density that it wasn't dyed glass. We decided to put liqueur in it anyway, just to see if it affected the taste. It did, and badly at that, so now these bottles hold flowers in the living room. Actually, the paint is peeling off now, and I'm tempted to help them along with turpentine and see if the underlying bottle is usable.
With some study, though, it's relatively easy to recognize most of the colors that are painted. Bright reds, some blues that are too royal, purples, yellows, and really outré colors are all most likely painted. A few years ago they started putting "Painted Bottles - Do Not Machine Wash" stickers on the painted ones, and for a while it was a great help, but lately the larger chains have gotten lazy, and are putting these stickers on all their bottles so they don't have to pay attention to which is which any more.
More recently, I've started going to brewer's supply stores, and there I've found what I'm glad I didn't find seven years ago: regular wine bottles at reasonable prices. They come in colors, but they're all essentially the same, boring round featureless bottles. But once you've got a reputation, and people come to respect the contents of the bottles regardless of the bottles themselves, then these are a good, economic alternative.
The best thing about these wine bottles is that they've all got the same size neck, and they take standard-size corks. I can't tell you how much time I spend looking for odd-sized corks for all the fancy bottles I've got. Quality control is something you just don't find in exotic bottles, and I don't have two bottle-necks alike. At least with real wine bottles, you can buy two dozen corks to go with a dozen bottles, get a mechanical cork-inserter, and know everything will work. I use a mechanical cork-inserter when the neck is about the right size, but all too often I have to resort to pushing the corks in with the palm of my hand, and my hands can get pretty bruised in the process.
I've only been at this hobby for ten years, and I haven't had many good batches that stayed on the shelf for two or more years until recently. In looking over my bottle rack, I noticed that a very old bottle of the cranberry liqueur, one of the most popular recipes, had turned. The liqueur had gone from a rich red color to a sickly yellowish brown, and there were brown clumps suspended in it. Remembering a few bottles of other varieties that had similarly turned, I decided that perhaps there was a pattern worth investigating.
Somewhere, somehow, I got a clue. When not sealed well, corks breathe, and they allow for some evaporation of the alcohol and passage of oxygen. I decided that that's what must be happening, that my liqueurs are spoiling because they're getting oxygen and losing alcohol. Originally, I thought that it was the corks themselves that were breathing too much, but after some more close investigation, it became clear that the corks were leaking - they didn't have a good seal to begin with.
The problem with the pretty bottles I use is that they're not made terribly well. They hold liqueur admirably, and don't break or leach strange chemicals, but the problem is likely that the inside of the necks just aren't made precisely enough. Any little wrinkles in the neck, or any real deviation from roundness, and the cork just can't fill the whole space. Air, water and ethanol will move freely in and out of the bottle, and larger objects, too, like maybe bacteria.
My first, easiest approach to this problem was to buy the mechanical corking device I mentioned before. It basically compresses the cork through a cone, and releases it into the neck of the bottle. The cork immediately expands back to full size, and presses itself into all the nooks and crannies of the neck that it can fit. And more importantly, the cork is pressed in more tightly and securely than I could ever achieve with simple hand-pressure. For the majority of the bottles I use, this is a definite improvement. There are still quite a few I have to do by hand, but I can always make sure those get consumed first.