Cause of BAD Scotch batches?

Bad whisky? Most likely it is either the result of 1) poorly executed distillation, e.g. including too much of the heads and/or of the tails of the run: i.e. too "wide" a "cut", and/or 2) bad wood, and/or 3) an old bottle with too much air exposure.

Sulphur is an obvious flaw, and caused from poorly handled wine casks. Poor initial quality oak, or whisky matured too long in a given cask or set of casks, can also mess up the whisky.

Cork taint?

When I am thinking of bad whiskies, I try to classify them in two categories: 1) bad ingredients and 2) bad process. In the first categorie I will include bad malt, bad water, bad yeast, bad peat and bad cask. In the second categorie, I refer at distillation, at the choice of the cask, the time of maturation, the malting floor, etc. For me, I estimate that pprocess is often the reason of poor whiskies but rarely of bad ones. Of course, there could be a rare case of bad use of chemicals (for cleaning or any other reason for that matter) for example, but at the end, most of the time bad whiskies are the results of bad ingredients. As for the sour herbal note that started the discussion between Benancio and me, I was guessing that bad storage of either the malt, the yeast or the peat could have ruin the taste. I was incline to thing it was the peat since it is a note I have encounter mainly on peated whiskies.

Some other factors: excessive sulfur candles and cleansers used on casks; shipping casks in warm weather (they can spell en route); using casks too many times after they have turned; problems in distillation process (stills can break); bad batch of barley (it can turn when it is being malted); whisky aged in ware house next to air pollution (truck and car exhaust by a busy road for example where the exhaust like the heavy gas/particulates it is settles down into the warehouse).

I too have gotten bad batches of Glenfarclas in the past (two to be exact, one was a 21 and one was a 25). The quality of Glenfarclas has unfortunately gone down. I traded my 40 year for some other whiskies due to what happened with the other bottles, I lost faith. When a Glenfarclas is good, it's REALLY good. But when it's bad, it can be really bad. I long for the Glenfarclases of 3-4 years ago. Not sure, but maybe it was a high point in production. One thing is certain, the old stock of Glenfarclas is prodigious and impressive.

I also got a very very bad bottle of Highland Park 18 a while back. It tasted as though it had detergent in it. This said, I did go back and get a very very good bottle of HP18 about six months later. Personally, I prefer HP's UK releases over the American ones, and I prefer HP's Scandinavian releases over it's UK ones. HP sends some real gems to Norway, for instance. And why not? The Norwegians deserve a great bottle of HP! (My dad's side is Norwegian, so perhaps I'm biased)

I also think barley grown in bad soil or with bad seed can affect the taste of whisky. I really like the European release of the Bruichladdich Organic. The American version is not very good. I also like the Scottish barley version. The Islay barley, eh, not so much.

Good small farm barley is often superior, especially with heirloom seeds. Most barleys today are grown based upon the amount of alcohol it yields rather than flavor. Most barleys today don't hold a candle to the seed used 60-70 years ago to make whisky. That is part of the reason that whisky made mid century tastes so good! And it is often the most overlooked reason. Why? Hint: the distilleries today like making a lot of profit. If the cat got out of the bag, it would cut into their bottom line to source better barleys, especially heirloom seed varieties.

@sengjc. Cork taint, that's a good one, it taste like it came from the taint area.

@rigmorole. Great response , I think your right, it comes down to the bottom line, money. If your right they know which batches are exceptional and who gets them. That would mean they also know that certain batches are bad and still decide to sell them. What do you think about a mash spoiling? would they discard it? I was at a distillery in Kentucky on a tour where they warned us to be careful around the mash. They told us that Someone had dropped a camera in the mash and other items. I asked what they did with the mash afterward, he gave me no response. I know they distilled it.

@victor. I have tasted bad distillation and white whiskey. It's awful stuff. Is that do to carelessness or again it comes down to profit?

@Robert99. I'm in agreement, there are probably multiple reasons from poor ingredients to carelessness.

If the distillers knowingly cut corners to increase profit while producing bad scotch, they will not get my money a second time. I will probably NEVER buy another bottle of Bunnahabhain or Glenfarclas again.

Genfarclas is very well known for its bad corks, so well you'll probably have your answer right there.

As for the casks, they can handle a whole lot of abuse. So I wouldn't care too much and Scottish distillers aren't idiots who would use bad barrels. The days of taking barrels apart and reassembling them seem to be over. More and more barrels are kept intact for transportation.

I trust the Scottish coopers know what they're doing.

Another explanation could be that there will always be a certain amount of bad casks. They used to be added in blends or sold as bastard malts. But as single malt whisky becomes more and more popular the chances of you getting a bad barrel at premium prices has increased significantly

@Pandemonium I'm sure the cooper aren't idiots. I do know most people take pride in their work. There always seem to be a few lazy asses that are careless and only care about their next paycheck.

Its the pressure the distillery workers are under from the distillery owner to produce high volume at the lowest possible cost that can affect decisions. Pressure can make people make bad decisions.

Barrels may be shipped complete now, but they are disassembled and reassembled by the coopers in Scotland. They have to be otherwise they will leak.

Bad corks play a role I'm sure.

@Benancio what @Victor said is really good stuff. I would also say that you would always want to allow for a certain amount of batch variation. All of @Victor's point ring true here, however new make spirit fermented and distilled a day apart will have some variation as well. (:

And when you get a bad whisk(e)y what do you do? Hope it improves in time and revisit it until it's all gone or split it with a cheap blend ?

@Frost, I vat my disappointments with other stuff or keep it around for "end of the night" drinking.

If you're Ralfy, you add maple syrup or something to the bottle. :)

If it's really BAD though—like faulty or spoiled—we ought to be reporting them to the retailers or bottlers.