I. Types of Sardines
Sardines can be found throughout the oceans and seas of the world, but they vary by region just as all types of seafood do. Sardines from Mediterranean taste different from Baltic sardines. The most important thing to remember is that the sardine fish is not always the sardine food. Labeling laws are not standardized in America and many other regions regarding small canned fish. Sardines can often really be brisling, sprats, sardines, pilchards, and other less common varieties. For the purpose of this guide, I will always refer to sardines qua food not zoology. The most common types of sardines will depend on the waters they are fished from -- Baltic, North Atlantic, and other cold regions tend to have more sprats and brisling, while warmer waters tend to have more sardines.
Keep in mind that many distributors have rights to multiple canneries. Roland, for instance, has canneries all over Western Europe and their product quality and packaging varies among the different canneries. Do not rely on distributor names for sardine quality!
III. Country of Processing
Most sardines will be processed somewhere in Western Europe and imported to the United States. A few Canadian companies exist as well. I have yet to encounter any canned sardine processed in the United States. The country of processing will always be marked in the United States as 'Product of [Country]'. Note that this does not indicate the waters it was fished from. However, the country of processing is generally indicative of the sardines' waters. This is not a comprehensive list, so feel free to suggest additions. I've listed the countries of processing in a descending order of general quality.
All the EU countries seem to have their information in a circle on the tin. It will say something like LV 44 Z, where LV denotes it comes from Latvia and the rest is the EU commercial approval number. Other countries will say things like DE GI-310 EG, where DE denotes German origin and the rest is again the approval number (I'm guessing some numbers are larger than others because of the higher number of EU commerce permits in those countries).
A. List of Countries of Processing
1. Baltic States
The Baltic States (Latvia, Estonia, Lithuania) are all members of the EU with fishing as an important industry. Most of the sardines are fished from the Baltic Sea and are sprats or brisling, with sprats being by far the most common. Sprats from this region are soft, plump, and small with a very concentrated flavor. They are often smoked but can be found canned in oil and unsmoked as well. People from this region have eaten smoked sardines for centuries. The sprats are usually first smoked before being canned with a light oil (sunflower oil tends to be the most common from this region, but I've seen rapeseed oil as well I think). The sprats imported into the US are mostly from Riga, the capital of Latvia and a large seaport with extensive fishing industry. These are the same sprats processed and canned the same way many Latvians eat them. The best varieties (and 95% of those I've encountered) come in a heavy tin and are labeled as 'Rigas Zelts'. These can be found for $2.50/6 oz. tin or less due to the relativity of the Baltic economies compared to the rest of the EU.
Germany does most of its fishing out of the North Atlantic, and the types of sardines vary. I've encountered mostly sprats and brisling from Germany. German imports of sardines tend to be from the same company that processes them. The three biggest are Appel, Rugenfisch, and Alstertor. These are either smoked or unsmoked, with the unsmoked varieties usually packed in some type of sauce. Appel tends to pack theirs in canola oil, Alstertor packs theirs in canola and rapeseed oil, and Rugenfisch tends to use vegetable oil (often soybean). There's more varieties than I've eaten, but in terms of general quality Appel tends to be the best. The mustard and dill sauces are my personal favorites for unsmoked sardines. I've even seen weird stuff like sardines canned in ketchup. They are usually canned via steaming, but sometimes are first fried and then canned with onions and/or chiles. German brands tend to be expensive ($3.50/6 oz. tin), but they're great quality.
Canadian varieties are usually brisling and sardines. I've seen both smoked and unsmoked varieties, but both aren't too great. I think most Canadian processors make them for the US market and therefore make them as cheaply as possible. The fish are good quality, but I swear they just throw them in the tins and then into the canner. These are usually plainly packed in vegetable or olive oil, with the olive oil varieties being obviously much better. I've seen lots of big seafood distributors with their hands in the Canadian market, including Roland, Ocean Prince, and I think Chicken of the Sea. These are relatively cheap depending on the distributor, so don't overspend because the product quality isn't generally worth it.
Polish varieties tend to be fished from the Baltic Sea and are usually sprats or brisling. I've seen only a few Polish varieties and the fish are as good quality as the Baltic States', but Poland tends to be cheap when they process their fish. I've only ever seen them in vegetable oil (likely soybean or canola) and I've only seen them unsmoked. The biggest importer of Polish sardines in the United States is Seasons' Brand, which for some reason prices their sardines above the value of their quality of processing.
Pretty much all Mediterranean sardines found in the US are processed in Morocco. The most common variety is a sardine. I've had some decent stuff from here, but I generally avoid 'Product of Morocco' since there's really no point in filling the distributors' pockets for what are often previously-frozen sardines. I prefer sprats to sardines themselves, since sprats tend to be better in almost every criteria, namely flavor and texture. Many are packed in vegetable oil, but the better varieties originating from the Mediterranean are packed in olive oil (or at least that's my guess). The biggest problem with Morocco is that it's a complete mystery where the fish came from, how it was handled, and even what kind of fish it is to begin with.
IV. Methods of Processing
Some sardines are first frozen before being canned. It's impossible to tell from the label which varieties are frozen before canning, but my guess is that the sardines that are not intact within the tin are likely frozen before canning. This is my list of distributors that I believe use frozen sardines from time to time:
Chicken of the Sea
B. Smoked and Unsmoked
This difference should be obvious, but with the smoked varieties look to see if they are naturally smoked. Some canneries put liquid smoke in the tin with the oil before canning. Liquid smoke may taste fine in other products, but it is not a substitute for sardines where the smoking process changes the fish in other ways, notably its texture.
C. Type of Oil
In my experience, lighter oils tend to be better. Heavier oils (the heaviest I've seen is soybean oil) are too stable and won't hold onto the flavor, especially with the smoked varieties. Forget about varieties in water -- they are not comparable in quality at all and should not be bought.
D. Processing Before Canning
Most sardines are minimally-processed before canning: they are sorted, their heads are removed and they are canned. The more they are processed and handled, the worse quality they tend to be. Some companies do a poor job of sorting the sardines by size and ruin some sardines because the tins are only inspected as a whole. Furthermore, some sardines are smoked before canning and some are fried before canning. I tend to prefer smoked. The fried varieties are rare and I've only ever seen them from German importers, but Spain, Portugal, and France I believe all sometimes fry their sardines before canning. If you see them from these countries, give me a heads up.
1. What To Look For
As a summary of the above, the most important criteria for the quality of sardines will be their processing: they should ostensibly be minimally handled, equally sized, and packed tightly in a sturdy tin.