An interesting question, then, is: Which countries consume mostly their own domestic product and which countries import their wine? This is the topic of this post.
The information comes from The International Spirit and Wine Record.* The graph below shows the data for those 80 countries with detectably non-zero production but where estimated wine consumption exceeded 1 million 9-L cases (a dozen bottles) for the year 2017. The vertical bars show us the estimated number of wine cases that are imported as a percentage of the total number of cases of wine. [Note: only every second country is labeled.]
Globally, imported wine consumption comprises an average of 33% of the wine market, which means that an awful lot of wine is being moved around internationally. However, there is apparently one country that does consume a lot of wine but imports next to nothing: Argentina (0.04% import).
There were actually 24 countries that each consumed >500,000 cases of wine in 2017 and yet imported <15% of their domestic consumption [Note: there really were no countries between 8.3% and 15%]:
Clearly, several of these countries have populations that mostly do not consume alcohol, and therefore domestic production is quite sufficient for their small needs. However, quite a few of the listed countries do have a large amount of wine production, and are well known as wine exporters as well as consumers (South Africa, Chile, Italy, Spain, Portugal ...).
Note that Spain and Italy are two of the world's biggest producers, and therefore it is unsurprising that their populations drink mostly the domestic product. On the other hand, France is listed at 21.2% imported wine, but this is likely to be the result of the many tanker loads of Spanish wine that the French import and add to their own production lines.
Australia is another well-known wine producer with relatively low levels of import (17.4%). Other well-known wine-producing countries with somewhat larger import levels include New Zealand (25.2%) and Germany (51.2%), both of which produce a fairly restricted range of wine types, and therefore presumably need to import the rest (the muscly reds, for example).** There is also the USA (27.3%), which imports mainly premium wines (see The USA imports more expensive wines than anywhere else).
At the other end of the spectrum, there are 16 countries that each consumed >500,000 cases of wine in 2017 and yet nominally imported 100% of their domestic consumption (in decreasing order of consumption):
Obviously, none of these countries are well-known for wine production; and yet several of them do, indeed, have commercial operations, albeit small.
For example, Vineyards in the EU lists these countries as having <500 ha of vineyards, and therefore are not included in the European Union statistics: Belgium, Denmark, Estonia, Finland, Ireland, Latvia, Lithuania, Malta, the Netherlands, Poland and Sweden. I can personally confirm the existence of vineyards and very nice wines in Sweden, Belgium and the Netherlands (see also the blog post on Bizarre wine data).
As a final point, it is worth noting that wine imports can have very specific goals in terms of servicing the domestic market. As but one example, 19% of the Australian wines imported into Sweden are labeled “organic”, and 49% of Australia's exported “organic” wines end up in Sweden (see Organic wine — a sustainable trend?). Indeed, organic wine is apparently an increasing import trend throughout the Nordic market (Sweden, Norway, Finland and Denmark). For example, c. 50% of Argentinean “organic” wine exports also goes to Denmark and Sweden.
* The data can also be accessed through the Wine Australia Market Explorer.
** In 2018, 75% of all New Zealand wine was made from Sauvignon blanc, mostly from the Marlborough region (see The question of supply). Germany is not quite such a vinous monoculture.