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David Robertson, Macallan Distillery manager, shares a cask sample that is being considered for the next bottling of The Macallan, 18.
The Scotch Doc comparing cask samples in The Macallan Sample Room.

Interview of David Robertson, Manager of The Macallan Distillery

By Dr. David "The Scotch Doc" McCoy

(The following is the text from an audio-taped interview that occurred in the Sample Room of The Macallan Distillery on the early afternoon of June 26, 1998. The considerable amount of time and patience that Macallan Distillery Manager, David Robertson, so generously provided me, from his very busy schedule, is much appreciated. I hope that you will, also, find the candid nature of his answers and his knowledge enlightening.

The purpose of the interview was to obtain data concerning the actual procedure and process that Manager Robertson and The Macallan distillery officials engage in determining the contents of a typical bottling of The Macallan. With education being the major objective of The Scotch Doc’s Scotch single malt endeavors, this was a subject that the literature never seemed to completely satisfy for me. After this rather extensive interview, I also understood how Manager David Robertson has come by his nickname "The Nose." For an individual as youthful as he is chronologically, he has gained a tremendous reputation among his peers, and certainly, those of us who enjoy the "fruits" of his art and craft. Thanks again, David.)

Doc: David, it is truly exciting being here in such an important room at The Macallan Distillery (The Macallan Sample Room). On behalf of myself, and for the many fans of The Macallan, could you share some of the process that you engage in order to determine the contents of a typical bottling of The Macallan? Let’s suppose that you have just completed a bottling of The Macallan and you are now at the very beginning stages of preparing for the next bottling of The Macallan 12 or 18 year-old. On that point, are there any differences in your preparation for bottling these two ages?

David: No. There is no difference. The process is exactly the same in identifying the casks for sampling for the next bottling. We go into the maturation warehouses and obtain samples from between 100 and 150 casks of the appropriate age (the age that we are bottling such as the 12, 18, 25 year-old.) We then bring the samples back to the Nosing Room, the room in which you now stand this afternoon, for consideration.

Doc: Looking around this room, I see several rows of probably 100 milliliter (3 ounce) bottles. They have several different shades of amber, with some being very light and some being very dark. These are all sherry casks, correct?

David:Yes they are. As you know we (Macallan) always use sherry-cask matured whisky for the Macallan single malt. But sometimes we fill a cask more than once. The combination of first-fill and second-fill sherry casks will produce several variations in color. The color of the Macallan is determined entirely by the influence of the cask. What you are seeing here is typical. The first-fill sherry cask matured whisky gives us a deep (dark amber) color and rich character. Obviously, a second fill sherry cask is lighter in color because the first filling has subtracted (leached) some of the sherry color, and other wood extractive components, from the cask.

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Doc: That seems logical enough. Okay, as I examine one of the several bottle samples here, I see the numbers and letters of the alphabet, "553-SB-82." This is, obviously, a code of some kind?

David: Yes. The "553" designates the identification number of the cask. The "S.B." tells us that the cask is a sherry butt. The "82" designates the year of distillation as 1982.

Doc: Here is a much lighter sample in a larger bottle with the number 6147. That would be the cask number, right?

David: Yes.

Doc: I see that it was distilled in 1985. Would the young age of this sample account for its much lighter color?

David: These samples come from American bourbon oak cask matured samples. A portion of Macallan’s business is selling "new make" (recently distilled spirit) spirit to the blending industry. They will choose whatever wood (cask) they like for their own blends. So we have two sales outlets for our produce, the provision of new spirit for the blended industry and the other, as you know, The Macallan bottlings. The larger portion of our spirit production, by far, goes into The Macallan. These larger bottles, such as the one labeled "6147 1985" is from an American oak bourbon cask that the blender would have supplied us to fill with Macallan new spirit.

Doc: I see. Now what is the situation on the other side of the table? I see two, seemingly, regular bottles of The Macallan 12 year-old sitting amongst thirty to fifty 100 milliliter (3 ounce) sample bottles.

David: Along with some general untidiness, the large bottles that you can see here have their crown tabs unbroken which indicates that it is a sealed bottle. For every bottling of The Macallan, after the casks have been selected and they have been vatted and married (blended), we take an actual bottle, selected at random, from the bottling line. Our quality control team, consisting of other Macallan employees and myself, take the bottle back to the distillery for final approval before the bottling is approved. Only with this kind of attention to detail can we be sure that this bottling of The Macallan has not been contaminated at the bottling facility. This also ensures that this bottling meets all of the standards of a classic Macallan and that it is ready for the market place, for example, in your Dallas, Texas.

Doc: So this is part of the well-known Macallan quality control?

David: Yes. As you can see here on the back label, we also have the "bottling run" number. This enables us to identify when a particular bottle was run and who bottled it. We can also check the filtration regimes etc., etc.

Doc: Up there on those shelves, I see hundreds of small bottles that contain absolutely clear liquid in them. What is this?

David: Those bottles are current samples of new-make spirit that has just been distilled. You see, we also evaluate the quality of the new-make to make sure that it has the right characteristics before we fill it into casks for maturing. We draw samples of spirit almost every day to make sure that the new-make spirit contains the desired estery, fruity and slightly oily character that we want for The Macallan spirit. We will check it again at the end of the week and make up a composite sample of the previous spirit runs that week. The other bottles that you see in front of you are from the other distilleries within the Highland Distillers Group.

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Doc: Interpret this bottle for me. It has the numbers 19/01 along with several other numbers and letters of the alphabet.

David: Sure. The numbers "19/01" mean that it comes from the filling designated as "period 19." As we read down the label on the bottle, we see "SRWV1." This informs us that this sample came from "Spirit Receiver Warehouse Vat #1." The remaining information informs us that the sample was drawn on May 18, 1998, and the alcoholic strength is 63.6 % by volume.

Doc: Again, the attention to details. Oh yes, I wanted to go back to an earlier conversation with you concerning the spirit cut at the time of distillation. The, seemingly extreme, narrowness of the cut really got my attention. Is it just about the most narrow cut in the industry?

David:We like to think of ourselves (Macallan) as being fairly unique in the industry in a number of things that we do. One of the fundamental things that delivers the quality of new spirit character that we are looking for is the very, very narrow spirit cut that we take. During the distillation spirit run, we begin to collect the spirit at a strength of about 73% alcohol and stop collecting the spirit when the alcoholic strength falls below 68%.

Doc: Does this not add significantly to the base production costs of the spirit?

David: Certainly. You see, our spirit stills are charged (filled) with only 4000 liters (1040 gallons) of low wines (or "wash"), which comes from the first distillation. Then the foreshots (head) and feints (tail) are recycled every spirit distillation. So by its very nature, due to the fact that we take such a very narrow cut, it means that we are having to recycle (redistill) a fairly large volume of feints and foreshots at every spirit distillation. Obviously, the broader/ larger the spirit cut, the less you have to recycle and the more economic the distillation expense becomes. However, it is very important to be able to influence the spirit character prior to filling the casks. With the more narrow spirit cut, we can better manage the spirit character prior to filling the casks and have confidence in the Macallan malt that we will be bottling in 10, 12, 18, 25 years, and even longer. In summation, it means that every time that we run our spirit stills, we only collect 640 bulk liters of spirit at 71% ABV (alcohol by volume) out of a charge of 4,000 liters. This amounts to only 16 percent of the charge.

Doc: So obviously, the higher quality spirit incurs more expense. This attention to detail, from the very beginning, along with the other quality control nuances, helps to explain the reputation of The Macallan that continues to grow.

Now what is the destiny of this grouping of bottles that contain several different shades of liquid?

David: This is a grouping of bottles that we’ve selected. We believe that they will go together very well, perhaps well enough, to become our next Macallan 12 year-old.

Doc:Each bottle, again, represents an individual cask?

David: Yes, each bottle is labeled with a number, cask type and year of distillation. I am putting together a small composite sample by using 50 different casks to give us the The Macallan that we hope to bottle. We will vat and marry a proportional amount from each cask to give us a balance of flavor that we believe will be consistent with our 12 year-old Macallan.

Doc: Will the cask types always be used in exact proportions?

David: No. It will depend on the cask type. For a hogshead, we need to add only half as much as we would for a butt since a butt contains twice as much (500 liters) as a hogshead (250 liters). This is one of the reasons for stating on the bottle, the size of cask from which the sample comes. It is for this same general reason that we record information such as first or second fill sherry filling. Macallan normally sells their casks after they have been filled twice – usually to other distillers. The reason for this is that the malt characteristics aren’t the same and are not acceptable for what we are looking for in our malt. As you know, The Macallan is a naturally colored malt. We don’t add any caramel. By vatting together our light and dark colored whiskies, we can obtain, not only the color, but the flavor characteristics that we desire, as well.

Doc: So the maximum number of uses for your casks is twice? Are there any exceptions to this policy?

David: In some very rare instances, if we discover a second-fill cask that still retains the exceptional maturation characteristics that we require, we would use it a third time. On the other hand, when we use a first-fill cask, and it fails to provide the product (Macallan character) that we require, it is rejected for further use by Macallan. There is a demand for these casks from various industries. Garden furniture and wood for smoking salmon are two such markets for our casks.

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Doc: I see a large assortment of half-liter bottles, much larger than the 10 milliliter bottles, on this table. Are these a combination of "cask sample" bottles?

David: Yes.

Doc: About how many cask samples are usually represented in one of these composite sample bottles and would you describe your method of selecting the "individual cask" samples for the "composite sample" bottle?

David: Our method at Macallan may be different than that of other distilleries in the industry but it works well for us in creating the Macallan that we export all over the world. Briefly, the process occurs like this: We use about 10 milliliters of sample whisky for each butt that goes into a vatting prior to bottling. If we use 50 butts in a vatting, then we have 500 milliliters of composite sample for every vatting that we make. We can then go back and check the components of every vatting for comparison of vattings or for any other purpose.

Once we arrive at the "composite bottle stage," we leave the sample to "rest" for 2 or 3 days. We then compare the new vatting sample with the last Macallan of this age that we last bottled, or bottlings that were released to the market several years ago. In making the final vatting selection, that will become the "next Macallan" for the marketplace. I, and three of my colleagues on the "nosing panel," will nose samples from four composite samples: the new vatting, the last vatting sample that was accepted, one from a vatting from two years ago and a vatting from four years ago. For purposes of objectivity, the composite samples are labeled "A," "B," "C" and "D." This ensures that we are minimizing any possible product shift that may take place from bottling to bottling and year-to-year. We, therefore, assess our new vatting sample "blind" against previous bottlings of The Macallan. During these nosings, we are looking for a consistency of character throughout all four samples. After selecting the "best matched" vatting, if we determine that it is too inconsistent, such as being too woody, spicy, fruity, dry, oily, musty, or whatever, as compared with the past Macallan sample, we go to the retained composite sample of that previous bottling (as explained previously). Then, with a lot of patience and more nosing, we ultimately determine what was unacceptably different and make the necessary cask sample changes to bring the current vatting in line with the previous Macallan character. We then have the new bottling of The Macallan that will be on the store shelves around the world.

Doc: What a fascinating process. I just hope I can transcribe this into a readable form for my readers. I am very impressed and feel a new respect for The Macallan that we all, so casually, take for granted – as well we should. Incidentally, how long do you retain the vatting samples?

David: We have vatting samples of the 12 and 18 year-old Macallan bottlings that go back to the mid 1980s.

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Doc: So, would it be fair, or would it be an oversimplification, to say that the composite sample and cask sample collection of bottles are, in effect, "The Macallan Library of Malts" to which they can refer in order to maintain the historical character, lineage and pedigree of future Macallan bottlings?

David: Yes. I like to keep such a library of samples for obvious reasons.

Doc: On one of these samples, I noticed considerable "beading," or an accumulation of small bubbles, when you poured it into the nosing glass. Could you explain this for my readers?

David: The "beads" give you an indication of the alcoholic strength of the whisky and other information.

Doc: The more beads, the greater the alcoholic strength?

David: Broadly speaking, maybe. The length of time that the beads remain, and the characteristics of the beads, will also give you an indication of the sort of oiliness of the spirit. It has to do with "surface tension" and alcoholic content. The higher the percentage of alcohol, the more beads you will get. How long the beads last, before they burst, will be influenced by the oiliness of the spirit. The more oil and viscosity, the longer the bubbles will last. I’m no expert in this nuance of the Scotch single malt but this has been my general personal observation.

Doc: David, I’d like to return to your demonstration awhile ago of what happens when you mix two different whiskies. As you slowly poured the darker malt into the lighter malt sample, the darker one seemed to go to the bottom of the glass and just settle there. Would you explain your point of this demonstration to my readers?

David: I was illustrating that when you mix whiskies together a complex set of reactions take place. You see, with two different casks, you may have two very different types of whisky. Just by pouring them together, not a lot may happen. It is vital that the different malts being combined be well mixed and that they be given time to, not only "mix," but to react to each other and stabilize. The Macallan bottling may include 50, 60, or 70 different casks for a vatting. This policy is designed to give us a complex and as broad a range of character as possible, but with as much consistency of character as possible. After the vatting meets our standards, the whisky is then filled back into the casks for the final step before bottling. The common industry term used for the "reaction" of the whiskies that occur, once it is satisfactorily completed, is "married." This gives the many different casks of whisky in the vatting time to stabilize. In the industry, many distilleries have chosen to discontinue the "marrying" process. Macallan not only continues this historical industry practice on site, but our sample room and testing is also conducted on site. Typically, with other distilleries, if the marrying procedure is practiced at all, it is carried out in the bottling facilities.

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Doc: From this most interesting explanation, could we not correlate the useful practice of allowing the splash of water that we pour and swirl in our dram to stabilize and "marry" before we taste it?

David: You are exactly right. Put a splash of water into your glass of malt, swirl it around to release some of the volatiles that you can then nose to enhance the taste of the malt. You see, water and spirit are completely different densities. Within the whisky you have a mixture of oils, esters and ketones which give the whisky character and flavor. By pouring water into the whisky, and drinking it immediately, you have not given the whisky and water components time to reach equilibrium or to "marry." At best, the drink will vary in character and flavor from sip to sip, until it becomes thoroughly mixed.

Doc: Even now, as I look at the bottle that you placed the darker malt into the lighter one, your point continues to be validated. Even after several minutes, the darker malt still sits at the bottom of the glass.

David: That is true. Nothing seems to have changed in the mix.

Doc: David, you have been most informative and I have acquired a greater body of knowledge pertaining to the production of The Macallan. I have also gained a deeper appreciation of The Macallan specifically, and the Scotch single malt production process, in general. As much as I appreciate the many nuances of the Macallan production process, how would you explain this complex operation to the "person on the street" in three minutes?

David: Not very easily but I will try with the following summary:

  • We sample 100 to 150 casks of whisky for every bottling of The Macallan.

  • We nose each of these casks and determine which 50 of the casks would best vat together to produce a whisky that is consistent with our previous bottlings of this particular age of Macallan.

  • We would then make up composite samples of the casks that are being considered for the bottling.

  • We then compare these composites with a composite of the last bottling of Macallan to determine a sample "match" that is consistent with the last bottling and previous bottlings from the "library" of Macallan malts.

  • Any character discrepancies are corrected by studying the cask sample options and making the necessary changes to bring the vatted sample to the quality we desire.

  • Once the nosing panel approves the vatting sample, the casks of whisky (of the composite samples) are vatted (mixed) together and reduced, with our high quality process water, (the same water that is used for our mashing step), to a strength of about 45% alcohol by volume.

  • The whisky is then filled back into the casks for marrying. The length of time allotted for marrying varies with the age of The Macallan that we are bottling. The 12 year-old Macallan is married for about three months, the 18 year-old for 6 months and the 25 year-old for 12 months. The malt is frequently checked throughout the marrying process to ensure that the "marriage" is going according to plans.

  • Once we are absolutely certain that the whisky is ready for release, it is sent to the bottling hall in Glasgow for bottling and packaging.

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That is definitely a comprehensive "nutshell" explanation. Now for my last question.

The Macallan is well known for its policy of using only sherry casks for maturing its whisky. What is the process used by Macallan to acquire their casks?

David: There are two primary ways in which we procure the casks in which we mature The Macallan spirit. One is where we select and harvest the Spanish Oak trees in the north of Spain. They are then cut into staves and air dried for a number of months. These bundles of staves are then shipped down to Andalusia, in the south of Spain, and on to Jerez de la Fronterra, located in an area known as "the golden sherry triangle." The staves are then further air-dried for two to two-and-a-half years in the significantly hotter climate than in the north of Spain. This is an important step since we don’t kiln-dry our wood, as some distilleries do. The casks are then constructed at cooperages in Jerez, Spain. The casks are then taken to various sherry bodegas in Jerez, Pekurto de Santa Maria or Sanlucar de Barameda, which are the three main "sherry towns" in the sherry triangle, in Andalusia, Spain. The casks are then "seasoned" in one of two ways:

One, the cask is filled with, a fermenting Mosto (grape "must")for a few months, which is later fortified with grape spirit to about 17% alcohol by volume to ensure the development of the Olorosa sherry. Fino sherries are fortified to 15 % alcohol by volume but we specify Olorosa as our preferred sherry type. The casks are later emptied and refilled with an older Olorosa for an additional period. The total seasoning period for the casks, that will later be used to mature The Macallan, is about 2 1/2 to 3 years.

The other way is essentially the "open market" purchase of quality sherry casks that meet our standards. For example, a sherry bodega may contact Macallan and offer for sale their casks that have been used to mature their sherry. Macallan representatives will go to this bodega and evaluate the casks by nosing the casks and the wine that was matured in them. If the quality of these casks pass our standards, we will purchase them. So essentially, we either completely make the casks from raw wood that we prepare or we purchase actual casks that were used by sherry bodegas to mature their sherry.

Doc: I am aware that sherry casks were once practically free and very plentiful in Scotland. Can you tell me what a typical, good quality sherry cask that meets The Macallan standards, now costs?

David: You are exactly right. Up until the early 1980s, when sherry was shipped into the United Kingdom in the casks in which it was matured, there was a glut of high quality casks. However, when Spanish laws were passed which required that their sherry be bottled in Spain, this abundant supply of cheap sherry casks disappeared. A good quality sherry cask now costs Macallan about $560.00 to $640.00 dollars. By comparison, a bourbon cask can be purchased for $60.00 to $80.00 dollars.

Doc: That is an interesting and dramatic change with a very expensive result for the distillery that insists on maturing its product in sherry casks, especially ALL sherry casks.

Finally, David, not only have you answered all of my questions, but you have expanded my knowledge in general and you have cleared up some "fuzzy" areas that were never completely clear for me. In short, you have enabled me to be a much better informed and more knowledgeable "Scotch Doc." I am indebted to you and my seminar/tastings and participants will be the beneficiaries of your generosity. Thank you very much.

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