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How long does sake last?
How long will unopened sake taste its best?
The answer: Not as long as wine, or as long as most merchants want you to believe.
Generally, artisanal sake keeps its fresh, lively flavors for a little less than a year from its release date. Most sakes have the bottling date written on the bottle, though they often use the Japanese imperial calendar, which counts years from the time a new emperor takes over. 2008 is Heisei year 20, which means if a sake is from year 18 (2006), look for another sake. They also might say 08 or 07; again, 06 is too old.
As always, there are exceptions. Honjozos can keep their crisp, simple flavors longer because of the added alcohol. Yamahais are more shelf stable and might last an extra year.
But generally speaking, you don't want ginjo or daiginjo sake that's two years old. Many importers simply throw it away, but grocery stores and wine shops loath throwing away product, so check the dates carefully.
Now here's a question: What happens to the flavor when sake gets too old? How can you tell?
It doesn't spoil and taste foul. The effects are much subtler, and I believe one of the reasons premium sake has had slow acceptance in the US is that many people have had sakes that are too old because they sat too long somewhere in the importer-to-distributor-to-restaurant chain.
Old sake usually tastes dull. Sake has lower acidity than wine to begin with; older sake will lose the perception of crispness, and taste flat. You won't likely smell or taste any of the fruity notes of fresher sake. Sometimes I get a slight acetone note. But when I encounter an old sake, my reaction isn't "ewwwww," it's more like, "aww," because I'm disappointed that there's nothing there. If you have this reaction to a sake in a restaurant, take a look on the bottle for the year.
How long does an open bottle of sake last? A little longer than wine, but not by much. And unlike wine, I don't believe I've ever had a sake taste better the second day: sake is always better the day it's opened.
Most sakes will still taste pretty good for 3-5 days, especially if you use a preservation system like Private Preserve (neutral nitrogen gas you spray into the bottle, it's cheap, most wine shops sell it, I'm a big fan). They'll still be drinkable for up to 2 weeks. After that I would cook with them. But always take a sip first -- that's how you learn to answer questions like this.
http://winerocks.blogspot.jp/2008/07/ho ... -last.html