During my first trip to Scotland in 1993, we toured the Glenfiddich distillery in Dufftown. I only remember a couple bits from this tour. First, I remember leaving one of the rooms because the smell made me sick. This smell reminded me of apple sauce. Second, I remember the guide gave everyone a sample of whiskey at the end of the tour. The guide tried to give me a glass, but Mom jumped in and told them to give me a glass of orange juice instead. I was 8, and I hated orange juice.
For undergrad I went to a conservative southern Baptist college, so I was a 'heathen' for occasionally drinking. After I turned 21, I had only drunk wine and sangria, but I wanted to try something new. One of my fellow 'heathens' took me to a 'pub' in Jackson where we got Newcastle ale and 12-year-old Glenfiddich. I enjoyed both of them very much because I love the darker, stronger and alcohols instead of the sweeter ones like white wine. At the time I didn't realize that I had been to the distillery where the whiskey had been made and probably around the time when the drink I was drinking was first brewed.
Though I don't remember much about the tour, my mom said that much has changed here in the last 17 years. There is a new restaurant where guests can try different scotches. Apparently, there wasn't a good parking lot next to the distillery, but there is one there now (from what my mom said, a lot of the tourist destinations throughout Scotland have improved dramatically during the past 10 years, even in Edinburgh). The new tour also includes a new movie that explained the distillery's history, specifically how the Grant family built the oldest buildings with their bare hands. Then a guide led us around to the different rooms, explained the equipment, and described the brewing process. We could take photos in almost all of these rooms except the warehouse. In the stills room our guide showed us how the whiskeys went through a second bath. I asked her how the scotch tasted at this point, and she said that it would taste like practically nothing.
The coolest part of the tour was the warehouse. Here, the guide showed us a video of a 'cooper' making a barrel for the freshly distilled scotch. This particular cooper was the fastest one in Speyside, one of the most important regions for scotch. He was about 3 times faster than the average cooper. Like other distilleries in Scotland, Glenfiddich makes its own barrels from used oak barrels from Spanish sherry and American bourbon producers. Unlike the oak used for sherry and bourbon barrels, scotch distilleries can reuse barrels over and over. Therefore, there is a huge excess of used sherry and bourbon oak barrels that the distilleries can import. The type of oak used influences the scotch flavor, so some scotches can have a strong sherry flavor. When making the barrel, the cooper looks at each piece of used oak to find a dark line in the wood. This line shows how far the previous scotch had soaked into the barrel, and once this line reaches the edge of the barrel, the wood is completely spent and will no longer add flavor to the scotch. Once the cooper makes the barrel, the distillery pours fresh scotch into the it. The scotch has to age for at least three years in order to be legally 'scotch.' If a bottle of scotch doesn't have a date or year on it, then it is probably 3 years old; the marketer would rather not put '3 years old' on it because it would then sound like cheap scotch. More times than not, the marketer will put the age on the bottle if it is 10 years or older. However, just because the bottle says '12 years' does not mean the whiskey is 12 years old; it only means the youngest whiskey in the bottle is at least 12 years old, so it could have whiskey that is 15 years old or older. Every year the scotch remains in the barrel, the scotch flavor changes according to how the oak influences it. Meanwhile, the whiskey gradually evaporates so that around 2% of the whiskey disappears every year. A 12 year old Glenfiddich loses about 24% of its original volume. Because so much evaporates, the older whiskeys are much more expensive. The whiskey that evaporates is called the 'angel's share' because this is supposed to be the magical bit angels drink in return for looking after us. In the Glenfiddich warehouse, there is a statue of angels sitting next to the barrels. Before we left the warehouse, the guides showed us three different barrels with different types of whiskey. One barrel was made from old Spanish sherry barrels; another was an old scotch; the last was younger. The guide allowed us to smell the whiskey in each barrel so that we would have an idea of how the barrel and age influenced the scotch. I was curious as to how the distillery made certain that the scotch tasted the same over time since the barrel could have such a dramatic effect on the whiskey: before bottling the whiskey sold in stores, the distillery pours several similar types of barrels into the same vat and lets the whiskey bond together for three months. This process is called the 'marriage.'
In the last room the guide poured us samples of the Glenfiddich 12 year, 15 year, and 18 year so that we could taste the difference between all the whiskeys. I've had 12 year multiple times, and one Christmas Mom bought me a bottle of 15 year. I've only had an 18 year once in a small sample box I found at a liquor store. It was very nice that they gave us these samples, especially since the tour was free. According to the locals, the 15 year is what Glenfiddich employes order when they go to the pubs.

Entrance to the Glenfiddich Distillery
Family tree of Grants who have
owned and operated the distillery
since they built it in 1887.
The mash turns where the Glenfiddich stream's
water first mixes with the fresh barley.
Cooking a whole bunch of barley with hot water.
The washback room. These brown barrels are only
the tops of huge vats where the sugary liquid produced from
the mash turn age for 3 months.
The alcohol grows in the liquid here, so these rooms have
a distinct smell. When I came here in 1993, the smell made me ill
so that I had to leave. The mash turn is like a tea room, and
the washback is like the brewer. The liquid here is similar to beer.

Inside one of the washback barrels.

This photo shows the rest of the washbacks,
which can be 20 feet tall.

The Glenfiddich stills.
Each still in each distillery is unique, and the
still's shape makes the whiskey produced
here unique. If the still is small and lets the
alcohol reach the top of the still easily, then
the scotch will be oilier than a scotch from
a taller still- I think that's right.

The old malt barn where the distillery used
to malt its own barley. The chimney in the picture
was part of the room where the barley was malted.
Today, Glenfiddich uses so much barley that it
no longer malts the barley on site, but the rest
of the scotch-making process, including
storage in barrels in huge warehouses, occurs
on site here in Dufftown.
This old malt barn is now a restaurant.

I couldn't take a picture of barrels inside the
warehouse, but I could take a picture of these.
A video from the tour.