Ask Beau - "How do you know when a sake is bad if you don't know sake that well?
The quick answer is if you did not buy that bottle from True Sake then indeed it is bad! Verrrrrryyyyyy Baaaaaaaaaad!
There are many easy ways to tell if a bottle of sake has "expired" before you purchase or consume it. And it's best to use all of your senses! First things first - check the label. Look for the release date, which basically is the day that that particular bottle was "released" from the brewery. If the bottle is more than two years old - buy or order at your own risk! Use your eyes. If you order a Daiginjo or a Ginjo and the fluid looks yellow - this is a pretty good indicator that that particular brew could be damaged. Typically brewers keep their higher end products clear, and oxidation is what accounts for the yellow hue. If the brew is old or has been opened for a while this color change is pronounced.
Smell! Just like in the wine world where you can smell a corked wine, in the sake world it is quite obvious if a bottle has gone south. Typically a sake will have a floral, fruity, ricey, nutty, or sugary aroma complexion (this is a generalization). If your nose immediately picks up musky, pungent, rotten, earthy, wet soil, mushroom elements then in all likelihood that particular sake has been distressed. (Some Junmai sakes or aged sakes smell like this in their pristine form - but these aromas are the exception in the Gino and Daiginjo space.) The nose of a damaged sake is probably the best indicator that the brew is no good.
Look again! Lots of bottles do not allow you the luxury to see the sake on account of their dark colors for obscuring purposes. So when your brew gets glassed then take a look at the color and texture. Do you see little floating elements? Run! Do you see a murky white cloudy perception? Run! Do you see dancing stringy stuff on the bottom of the bottle? Run! Basically all of these conditions are the results of the sake falling apart. The proteins loose their balance and change into goo globs similar to a lava lamp.
Taste! This is where the rubber hits the road. Why? Because even if a sake is distressed, abused or off and it still tastes okay, then there is no problem. If you like the taste, stick with it - even if the nose is putting you off! But if you don't like the taste and it matches the yellowish color and musky nose, and the balance has fallen away then return the bottle. Any retailer or restaurant worth their salt will gladly recall a damaged sake if you point it out! Heck, we have replaced perhaps 7 sakes in 7 years from customers who complained the sake was bad. In 4 of those cases the customers were correct. In three cases they just didn't like the style of sake that exuded those elements.
The bottom line is that you do not need to know sake well, to find damaged sake! It's as simple as doing a dust-on-the-bottle check! So fear not Marc - when a sake is "bad" or "off" it will provide you with a myriad of warnings. The trick is to use all of your senses! Including your "spider sense."
Please send your sake specific questions to askbeau2 @ truesake.com. (This address is not for general questions and I only review the questions once per month. All other correspondence should use info @ truesake.com.)