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Sherry Flavors As Key Components In Millstone Whisky

I previously talked to master distiller Patrick van Zuidam out of The Netherlands about growing rye and the impact of small grain. Today we continue this conversation with the exploration of the new warehouse, whisky barrels and sherry flavors.

Spread out on the parking lot of Zuidam Distillers BV in Baarle-Nassau The Netherlands,  I come across a few fermentation tanks which are ready to be installed. I spot a 2.5 inch tank insulation and some rings when I peep through the opening. ‘These are the tanks we bought from a Dutch multinational dairy cooperative, Campina’, Patrick van Zuidam, master distiller and managing director, explains. ’Together with the ones lying inside they add about 55.000 gallons to our present fermentation capacity. The costs of new tanks go up to $55,000 and these used tanks fit in perfectly. What you see on the inside are the rings that regulate the temperature; a necessity for a dairy company but also perfect for us, because this way we can set a repeatable result’.    

A heavy shutter rolls upwards and before me I see a vast area of 1200 square metres. ‘We realized this in 2016. In the corner you see two 8000 gallon beer fermenters. For two months ago this was a barrel storage filled to the roof with about 2500 barrels. We had to lower the concrete floor to accommodate two Forsyth stills; a hell of a job. I am surprised to hear that the assembling of the stills is done entirely by Patrick and his staff. Behind the stills you find the new wide gap heat exchanger, there to handle all the sticky rye’.     

The distillery room is full of noises: puffing and hissing, creaking and bubbling. ‘We distill malt whisky every day on this side and every six weeks we change making malt wine and rye whisky on the other side’. Knowing that people in the industry think differently about this I ask Patrick if the rye grain is primarily responsible for the taste of my rye whisky? Or is it the the spicy tones due to distillation and the interaction of the new make and the wood? ‘It’s the rye, definitely. You, know, Fred, there are too may opinions in this line of work’. Saying this Patrick taps a glass of malt wine from one of the stills. ‘This is malt wine, genever. A mash bill of 33% rye, 33% corn and 33% malted barley’. I smell and I taste; he’s right. The rye is certainly a dominant grain in this combination.    

image via Fred Blans

The new built storage rooms of Zuidam Distillers BV is like an office block: smooth concrete wall panels, a huge automatic shutter door, triple glazed PVC windows in the office extension and a huge parking space outside. The enormous shutter door slowly opens.  Patrick points out the sprinkler installation. ‘Unique in the world, a sprinkler on CO2 gas. We had to put this in because the provincial Environment Committee insisted. It makes our position as a company quite difficult when it comes to competing with colleagues in the business who set up a storage building like this for a price which is fifteen times cheaper’. 

OK, let’s talk wood maturation. ‘Quite a lot of Millstone spirit is put on Oloroso sherry butts, but things have developed. To be honest. It was purely coincidence and it has happened over the last five years. I bought the inventory of an entire bodega and they told me it was only Pedro Ximénez. The first two trucks were indeed; the third one was filled with 120 Moscatel butts. It made me curious and I filled the Moscatel barrels with a 5 y.o Millstone. The result after 2 years was quite interesting. I continued the experiment by putting a new make spirit in the Moscatel barrels. Again, a great experience.

With Oloroso there are currants, raisins and dried fruit; a bit sweet in the nose and dry in the mouth. PX gives us tones of laural, tones of licorice and some chocolate. Whereas spirit on Moscatel barrels present us tones of fruit and flowers’. 

I spot some solera barrels in another of Zuidam’s steel racks. ‘They’re obviously worn off barrels used to make sherry’. The solera system is made up of several rows or tiers of barrels (aka criaderas or nurseries) on top of each other. The bottom row is called solera as well. Every year part of the wine from the solera is bottled and therefore wine from the other nurseries is needed to fill up the barrels from the lower tiers. A solera is essentially a never-ending ageing system, gradually but slowly growing older. 

Patrick has a constant focus on wood management. ‘I often have to act within a few hours whenever barrels are offered on the market. For us this is way more difficult than for instance Macallan. They do about 100,000 seasoned casks a year which are made for them on demand’. Half of the activity of Spanish bodegas is seasoning whisky barrels. Before ending up as sherry-vinegar the sherry used for seasoning will be kept into oak casks for a period of 12 to 18 months. This exercise can only be done four times before the sherry has lost its power.    

While talking about the great variety of barrels we stop in the middle of the warehouse. ‘Over there you see some Italian red Amarone wine and some port. However, even more interesting are the white wine casks down there. And further on you see 160 Portuguese Moscatel barrels I bought the other day’. It feels like being in a barrel shopping mall when Patrick stops to let his hand rest on another barrel. ‘These used to be Oloroso sherry butts, but had to be rejuvinated and downsized to 250 liters. Look, as new’.

We walk down the warehouse to take a look at some casks with galvanized hoops. ‘These rye whisky barrels were filled in February 2017 and made by Kelvin Cooperage from Kentucky; air-dried for 24 months and charred. These virgin oak casks are $ 250 each, whereas those sherry casks go up to $ 900’.

‘From the whole range of sherry casks these Palo Cortado are mavericks, really outstanding barrels. Palo Cortado, Manzanilla and Fino are all made from the same young wine. Depending on how the wine matures it turns into Fino. A lot of esters are released in the process because the oxygen levels are diminished to a minimum. This is how you get a bleak, light colored wine. Oloroso is made from the same basic white wine but without the flor (wild yeast). It takes Fino about five to six years to turn into Fino in a solera system. If you decide to siphon this Fino into another cask without flor after a few years it will turn into Amontillado. This is a sherry that went through the whole maturing process of becoming a Fino and oxidized in the end. A very interesting wine indeed. Then there is the Palo Cortado, which basically started off as the black sheep of the sherry family. It used to be a Fino prone wine that stumbled on the way; a bad Fino so to speak. All these sherry wines have their own characteristics. But these Palo Cortados are extraordinary. Cortado barrels a rare and he price is soaring at the moment. Only last year my 6000 euro bid per barrel was topped by somebody else in minutes. Luckily I managed to buy 84 hogsheads; expensive though, but Palo Cortado’.

‘In the first contact when the spirit touches wood it extracts the most interesting color, taste and aromas. Over time the absorbance capacity decreases. Whenever you buy a 4 y.o. Kentucky whisky barrel you might ask yourself if the complexity is still there’. By buying virgin oak Patrick knows in what kind of ‘marriage’ he ends up in. There will be more depth, more wood influence and more interaction in comparison to the older casks he uses. ’I am always seeking for balance. Before ageing our whisky on a 10 year old barrel we often start off on virgin oak for about six months. This way the ‘marriage’ generates a wonderful color together with the oxidation of a 10 year maturation. There’s always the disadvantage of the virgin oak getting too much of the upper hand over the spirit itself. However, if you age a rye whisky – which really is a spirit with balls – on virgin oak you create a level playing field for both wood and spirit. A delicate single malt whisky would surely have been dominated by the wood extracts. Most of my rye whiskies are aging on virgin oak, a few on Oloroso and on PX’.

Back in the office Patrick pours me two drams: a Millstone Peated double maturation American oak Moscatel (46% abv) and a Millstone Peated Oloroso sherry (46% abv) from the  same batch. The first one is light of color and has floral and fruity tones; the latter is of darker color and has more mouthfeel. ‘These butts are from a different solera tier (‘criaderas’). The one from the top tier has fruity tones: apples and pears, in the other group from the bottom you sense floral tones, esters and jasmine’. Whenever Patrick blends the different butts, the selection is not only on age. ‘I take samples from every butt and make a vatting. Of course this is always done by hand’.  

Maturation is a combination of more elements than one. ‘First the extraction from wood is crucial. Even more important is the way the elements in whisky oxidize. They change by oxidation and react with elements coming from the wood. Because these reactions are ongoing older whiskies grow more complex’. Till it comes to a point that the ‘dead barrel’ has nothing to offer and therefore cannot react anymore. ‘So on the one hand it’s the interaction between wood and spirit and on the other hand the interaction between all the oxidation compounds. We know that wood is responsible for coloring the spirit. Still it’s quite unpredictable to generate the same final color in your whisky. Identical colors should be the final outcome in the same cask whether you age rum, jenever or whisky. But this is not the case. A richer spirit, one containing higher alcohols will react more aggressively than a triple distilled spirit. So there’s a different interaction with the barrel’.  

Being in the business for 25 years now makes Patrick van Zuidam an expert when it comes to deciding which barrels to buy on which char levels. ’Once I had aged one of our spirits on virgin oak in 1996. I had expected a dominance from the wood because of the extraction. But after 20 years after I dug out the barrels from a corner of my warehouse, and it turned out to one of the best whiskies I had ever made. Sometimes colors fluctuate but although we never caramel color the outcome can differ. This is also the case for finishes on PX barrels. A lot of people don’t agree with me on this, but these have been my most successful whiskies: 4 year old spirit aged in 4 to 7 year old barrels’. 

There’s a pause in Patrick’s story and I seize this opportunity to raise my glass to a family owned and family run distillery on the move. 

Fred Blans

I write about all sorts of beverages of which whisk(e)y is my favorite. Traveling, interviewing and writing are combined in most of the stories on my blog. I have to admit that the occasional cigar is a companion that I love to pair with food, (port) wine, cognac and again whisk(e)y. My journeys through Europe have taken me to the most amazing distilling venues from Islay to Poland and Italy to France.

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