Coolships in Oregon: A Trend for 2018 and Beyond

Coolships in Oregon: A Trend for 2018 and Beyond

In September, I co-wrote an article with Pete Dunlop for the Oregon Beer Growler about coolships in Oregon. The article ended up being much smaller than we anticipated, and most of the information that we had collected had to be paired down significantly.

Over the course of several months, Pete and I toured breweries to talk to brewers. We also conducted email and phone interviews, for a total of twelve. Each place had something unique to say about what inspired them, and I felt it necessary to share more of what we gathered. It’s taken me some time to collect and organize the content, but here it is!

What is a coolship (or koelschip)?

A coolship is a vessel used for the cooling of wort, typically for the creation of wild or spontaneous ales. No yeast is added, but plenty of natural yeast and bacteria from the air gets in. This is encouraged, as each climate is unique. The beer is typically aged in barrels and blended for optimal results.

Here in Portland, we’re all about our local products. Using a coolship is definitely a way to embrace that idea to the fullest. Coolships aren’t new by any means, but they’ve been installed in higher frequency in Oregon this year. It spurred the exploration into the subject for the Growler article, and I hope you enjoy reading a little more in-depth about their usage.

The interviews below are arranged in alphabetical order and sectioned out by question for easier reading.

Full List of Coolships being used in Oregon and Southern Washington

Upcoming Coolship Installations

  • Von Ebert Brewing (East)
  • Little Beast Brewing

Design Element 50x50The Ale Apothecary – Bend, Oregon

Interview with Paul Arney, Founder & Head Brewer

PDXBeerGirl Coolships Ale Apothecary Kuurna

Could you list the names of the people who have helped hollow out the spruce tree?

Jacques Bourque has been the main carver. He’s the fellow that was sitting in our tasting room and offered his help, so I took him up on it. He spent the better part of a week working on it. Ethan Edwards from Ben’s Bottle Shop in Vancouver lent a hand for a day. Herb North is a local finish carpenter and good friend who is helping with the bulkhead fitting and Hans Schopen who works in our cellar is fitting the heads.

You’ll be using it for both a coolship and lauter tun?

We will use it for both a lauter tun and coolship, but probably using it mostly as a coolship. We’ll only use it as a lauter tun (a la kuurna) when brewing our Sahali and whenever we want to get really old school.

Do you know approximately how long/wide/deep the tree is?

The tree is 14 feet long and we cut a 14” x 14” section out of it that we are widening as much as the tree will let us. It will hold four barrels. 

PDXBeerGirl Coolships Ale Apothecary Kuurna Close Up

You mentioned possibly making it mobile, but where do you plan to install it?

It’s permanent home is still undecided…it’s freaking huge!

How often will you use it? Is there a particular time of year?

I imagine we’ll use it at least twice a month through the fall, winter and spring. Less during the hot months.

Design Element 50x50Allegory Brewing – McMinnville, Oregon

Interview with Charlie Van Meter, Head Brewer

PDXBeerGirl Coolships Allegory Brewing Closed Tank

When did you install your coolship?

Fall of 2017.

Where did you get it?

It’s a tank on loan from our good buddy Anders Johanssen.

Can you provide a brief description (mainly interested in type of material and shape)?

We are using an old dairy tank with removable Lids. It is all stainless steel and has a jacket on the bottom that I have run ground water through in intervals to nudge the temperature in a typical coolship curve.

PDXBeerGirl Coolships Allegory Brewing Dairy Tank

How often is it used? Is there a particular time of year?

We first brewed into it last fall with our good friends from Logsdon Farmhouse Ales. We didn’t find the right window this Spring to brew into it again but intend on many more brews beginning this fall. I am particularly interested in some spontaneous fermentation’s while the many wineries surrounding our brewery begin crush this fall.

Did you research the airborne fauna before installing?

We did not do any test batches. Just went for it on a full scale test batch last fall. It is fermenting and conditioning well and are optimistic about our future brews!

Design Element 50x50Block 15 Brewing – Corvallis, Oregon

Interview with NIck Arzner, Founder & Head Brewer

PDXBeerGirl Coolships Block 15 Brewing

When you did install your coolship?


Where did you get it?

I had Metalcraft fabrication make it for us.

Can you provide a brief description (mainly interested in type of material and shape)?

Our coolship is a stainless steel rectangle. I had it fabricated twice as deep as needed so that we can also use it as a double batch open fermenter. There is a jacket on the bottom to help control fermentation temperature when used in that manner.

PDXBeerGirl Coolships Block 15 Brewing Cellar

How often is it used? Is there a particular time or year?

As a coolship we use it around 15 times a year. We use it year-round as it is placed in our cellar which maintains appropriate temperature.

Did you research the airborne fauna before installing?

No. We did place it in our wild cellar with the thought that the resident flora was built up. I didn’t have a lot of hope for the first batches and was pleasantly surprised when they matured into great spontaneous offerings. Currently some students from OSU’s fermentation science program are tracking the evolution of different microbes within the barrels of our spontaneous program.

Design Element 50x50Brothers Cascadia Brewing – Vancouver, Washington

Interview with Jason Bos, Head Brewer

When did you install your coolship? (Someone told me it was mobile, is that accurate?)

We first picked up our koelschip February 8, 2018. It’s been installed atop a trailer so it could be mobile, as we share it with another brewery. It also opens the way for fun collaboration potential.

Where did you get it?

We bought it from Glacier Tanks here in Southwest Washington.

Can you provide a brief description (mainly interested in type of material and shape)?

It is made of stainless steel. It’s 10’ 7” Long, 6’ 1” Wide, and about 2’ 2” Deep (it’s pitched towards the drain that measurement isn’t constant). It is a pretty standard shape for koelschips.

How often is it used? Is there a particular time of year?

We are hoping to use it 5-10 times a year. The optimal time to use it seems to be when the outdoor temperature drops to around 30*-40*F, so we are typically using it through the winter months. This last koelschip season we used it once and look forward to using a bunch more this winter.

Did you research the airborne fauna before installing?

We didn’t do much in the way of testing our particular microflora where our brewery is prior to acquiring our koelschip, but we are really excited to see the evolution of our barrels that we have going and taste future brews as our spontaneous programs grows.

Since it’s shared with Feral Fermentation, what do the logistics look like?

We are sharing the koelschip and using it independently of one another. We can schedule times for us both to use it relatively easily. As far as us collaborating with these spontaneous endeavors… we will see.

Was it part of your original business plan to incorporate a coolship and coolship beers? What’s the strategy behind adding one?

It was definitely always part of the plan for Brothers Cascadia to make the jump to brewing spontaneous/koelschip inoculated beers. We were lucky that the stars aligned and we were able to get one as soon as we did. Mixed culture sour beers have been a part of Brothers Cascadia from the start and we wanted to really explore more of the dynamics that “spontaneous inoculation” has to offer.

For us the strategy is to build up some barrel stock of these beers and try to define our process in the meantime. It’s definitely going to be a lot of learning in a style of brewing that takes some finesse. We are going to want to learn about our koelschip, wort production, terroir, barrel management etc. We are very excited to build up some stock of spontaneously fermented barrels and blend together some fun new beers.

Design Element 50x50Feral Fermentation – Portland, Oregon

Interview with Ryan Buxton, Head Brewer at Ex Novo and Founder of Feral Fermentation

Was it part of your original business plan to incorporate a coolship and coolship beers?

I have wanted to start a lambic inspired brewing operation for a few years now. I have always been fascinated by mixed culture fermentation and have been playing around with numerous lab grown yeast and bacteria cultures for nearly a decade now. I tried to mimic Belgian sour producers through careful inoculation of domesticated wild yeasts and bacterias at various stages of fermentation and maturation.

For me, it wasn’t really until breweries like Russian River, Allagash, Jester King, De Garde, Black Project etc. started popping up that I thought about trying to brew in the same tradition as many Belgian Sour producers, through the use of a coolship. I had always heard rumors or romantic stories about the very special places along the Zenne Valley or the Pajottenland where these mystical yeasts and bacteria were supposedly uniquely found living.

Turns out that isn’t really true. There are several American Craft breweries who are making spontaneously fermented wild and sour ales using the microflora indigenous to their surroundings, and doing it well. This inspired me and gave me the courage or at least the hope that I could also find success in what organisms might be living in the area immediately around the brewery where I work.

So, I suppose that is a long way to answer your question, in that the whole concept of this side-project I am starting is 100% focused on making purely spontaneous beers, using local ingredients, with respect and inspiration from Lambic producer’s traditions.

How often is it used? Is there a particular time of year?

I intend on using our coolship in season, similar to how Lambic producers use theirs. Which would be in the late Fall and early Spring, when temperatures are cool enough to support the most ideal cooling rates for the surface area we selected for our coolship. I look for clear nights that get down between 33-38°F. I don’t have any intentions of making a large volume of beer. I’d like to keep the operation small, manageable for myself and maybe one assistant, so I will probably use it no more than 10-12 times a year.

Something in the air where you are?

There is something in the air everywhere on earth I believe, and this certainly seems to be the case here in North Portland. I was able to brew 3 batches this last Spring between February and March. I have 20 wine barrels full of 100% spontaneously fermenting wort.

I brewed a very traditional light wort that was about 11°P, with a grist comprised of all Oregon grown malted barley and unsalted wheat, and aged whole leaf hops. I have tasted and tested a select handful of barrels and find that they have had some slight acidification, as well as attenuation. The flavor profiles vary but I have found them to be quite pleasant so far, albeit young. I am looking forward to seeing how they continue to develop over time.

Design Element 50x50De Garde Brewing – Tillamook, Oregon

Interview with Trevor Rogers, Co-Founder & Head Brewer

PDXBeerGirl Coolships De Garde Brewing Trevor

When did you install your coolship?

We have been working with our coolship since the beginning of 2013, and have always been dedicated to spontaneously fermented beer. It’s why we are brewing in our location, and the process produces beer that speaks to our taste as well as our specific location. We added the second coolship (really, an expansion of the first) about two years back when we added a new mash/lauter tun, doubling our potential batch size.

Where did you get it?

Our coolship(s) were made by Practical Fusion, here in Oregon. We worked with them to design one that accommodated our batch size(s) and provided an appropriate and ideal rate of overnight cooling. Just as we utilize almost 100% local ingredients, we also want to work with local artisans, craftsfolk and businesses.

Can you provide a brief description (mainly interested in type of material and shape)?

We actually have two mirrored coolships. When we increased our batch size, it made more sense to add a second and identical one than to construct an entirely new and larger one. The total area is 13′ wide by 16′ long, with an interior height of 1′ and height including legs of just over 3′. The gross volume is 25 BBL (a bit over 12.5 BBL each), though our volume into coolship typically runs about 17-18 BBL. Fill height for each brew is about 8.5″ on average. After evaporative loss, we yield about 16 BBL of wort, which is perfect for us to fill either four 500L puncheons barrels, two 1000L oak casks, or one 2000L oak cask.

Both of our coolships are connected by a tee, so they fill at the same time and rate from the kettle, and empty similarly. We want wort consistency for each vessel after leaving the coolship. They are made of stainless steel. I’ve not yet seen quantifiable evidence that the material of the coolship makes a notable difference in the wort/beer produced beyond conjecture or cooling rates of specific materials (which can be normalized through depth and surface), and some of my favorite Belgian breweries use stainless.

If some our biggest sources of inspiration find it to be good, and their beer is fantastic, then how can I argue against it? Copper is certainly prettier, but at a higher cost, higher maintenance, and no qualitative difference. We fight to keep our costs and the associated prices to consumer down, not to find ways to make them both higher.

How often is it used? Is there a particular time of year?

We brew based upon the temperature, which limits our brewing season. We would like a consistent overnight low temperature in the low 40’s, which makes our historic potential window for brewing from mid October well into May. We have seen that continually shifting, with our season starting well into November this year, and our anticipated end coming much sooner. As a small brewery, we need to brew about 1,200 BBL, or seventy-five batches per year through our coolship and into oak.

Did you research the airborne fauna before installing?

We did. We targeted the Northwest coast as likely for success in this manner of brewing because of the temperate climate, and settled on our area based upon small fermentation trials. Certainly, folks are making great spontaneous beer elsewhere, but my wife and I personally favored this location for its unique quality and consistency. Just as we were excited to start exploring what this area had to offer, and continue to work with our native yeast(s) and bacteria to produce different and better beer, we are inspired by the exploration happening elsewhere from both new and established breweries as well.

Design Element 50x50Dwinell Country Ales – Goldendale, Washington

Interview with Justin Leigh, Founder & Head Brewer

When did you install your coolship?

We got our coolship last summer before we opened. It was actually the first piece of equipment we received, prior to the arrival of our brew system and conical fermentors.

Where did you get it?

We purchased our coolship from Loowit Brewing Company. They previously used the vessel as their mash tun.

Can you provide a brief description (mainly interested in type of material and shape)?  

Our “coolship” is not a coolship per se, but rather a modified 10 bbl dairy tank that’s made out of stainless steel. Since Loowit used it as their mash tun, it has a removable top as well as a removable mesh screen inside that can function as a false bottom.

How often is it used? Is there a particular time of year?

We actually use this vessel for a number of things – open fermentations, as a fruiting vessel, and for “open cools.” Generally speaking, coolships work well for open cooling of wort when the evening ambient temperature drops below and remains consistently under 45ºF. This, of course, depends a lot on the geometry of the vessel and the materials that comprise the vessel.

As you may learn in your research into this subject, there’s a few reasons for this temperature preference: first, you want the wort to cool efficiently, which usually means from boiling temperatures down to 75/80ºF in 8-12 hours; second, the colder temperatures tend to limit the ambient presence of bacteria, including lactic-acid producing bacteria, thereby giving brewers a higher likelihood for capturing inoculant with a higher concentration of wild sacc and/or brett.

Now, due to the design of our vessel, we need the ambient temperature to remain much lower. This is because our vessel is a lot deeper and narrower than most coolships, which are usually wider than they are deep. Plus, our vessel has a jacket of insulation, which tends to retain a lot of heat.

For this reason, we limit our open cooling to the winter months when it’s consistently below freezing temperatures. We’ve considered removing the insulation from our vessel, but we figured it would limit our other uses of the vessel. Even so, we wanted to test the results of our open cooling from a sensory level before we embark on that project.

With all that in mind, due to the rather mild winter we had, and our limited access to barrels in the winter months (our local wineries tend to empty barrels in the summer), we performed open cools with our vessel 3 times this past winter (figure, 12 of our current 42 barrels… so about 28% of our barrel program).

Did you research the airborne fauna before installing?

Initially, we picked Goldendale for our brewery’s location and also decided to perform open cools sight unseen. Early on, we considered purchasing a more traditional “coolship” (you know, wide, shallow, etc.), but when Loowit offered us their old dairy tank, we thought we’d save some money and give that vessel a shot. Plus, as a mentioned above, we could use the vessel for other purposes. Even with our current vessel, we still have plans to purchase a better designed coolship that will occupy a separate vented room adjacent to the brewery.

In the meantime, we’re experimenting with the vessel we have. So prior to performing any smaller captures, we essentially decided to roll the dice and open cool some of our beers. A few brewers I spoke with expressed skepticism about the viability of the micro-flora in Goldendale’s high desert climate, but we figured there had to be wild yeast and bacteria that would, eventually, turn our wort into good beer.

Later, after we purchased the building for the brewery, we brewed a number of test batches and performed a few open cools. We also setup wild captures in a few nearby fields, including a small local apple orchard. Those results were hit or miss.

Our best capture, however, came from our brewery. We have since worked with Jess at Imperial Yeast to isolate this strain and have it identified. It turns out we captured a pretty awesome brett brux strain. This, I’m told, is relatively difficult to accomplish because most wild yeast is some form of a wild sacc strain. Either way, we’re currently working with Imperial Yeast to propagate this strain, which we intend to add to some barrels, use for primary fermentation, and for bottle conditioning.

Was it part of your original business plan to incorporate a coolship and coolship beers? What was the strategy behind adding one?

Yes, we’ve always intended to open cool beers and incorporate some kind of vessel for performing that cooling process. Like I mentioned, we’re currently experimenting with a non-traditional “coolship,” but we still have plans to custom design a coolship that’s more suitable for our brewing process and climate.

Other than our recently mild winter, we are also limited by space. The inoculant from open cools takes a long time to mature beer. Plus, if you want to mimic Geueze-style blends, you need a few vintages of barrels to use for blending purposes.

On top of that, of course, some barrels don’t end up tasting very good, so you need to hedge against some liquid going down the drain. And as much as we’d like to stockpile barrels of open cooled wort, we also like to barrel-age other types of beers. But it’s a start.

We only just opened last August. As we start to bottle up some of our other barrel-aged beers and test the development of our open cooled beers, we’ll be making some decisions about what shape we’d like our barrel program to take. It remains to be seen whether we’ll focus more of our efforts on harnessing the power of wild yeast through an open cool method or simply propagating smaller wild captures from throughout the Klickitat Valley.

Either way, the strategy remains the same – to rely upon our local microflora in an effort to create beers that convey a sense of origin.

Design Element 50x50Flat Tail Brewing – Corvallis, Oregon

Interview with Dave Marliave, Founder & Brewmaster

When did you install your coolship?

Our Koelschip was one of our original vessels.

Where did you get it?

It’s a converted dairy tank formerly used by Calapooia and Oregon Trader Brewing as an open fermentation vessel.

Can you provide a brief description (mainly interested in type of material and shape)?

It is a jacketed, open top, rectangular vessel with a round bottom.

How often is it used? Is there a particular time of year?

Rarely, generally in early spring or fall when we get the most yeast activity coming off the river front, and no more than once or twice a year.

Did you research the airborne fauna before installing?

One of my first projects at Flat Tail was isolating yeast and bacteria strains from local fruit sources. There’s so much airborne microbial activity that we can see a kreausen on wort samples within 24 hours during peak season.

Was it part of your original business plan to incorporate a coolship and coolship beers? What was the strategy behind adding one?

Yes. Part of my original strategy was incorporating both traditional spontaneously fermented sour beer and also newer techniques revolving around stainless fermentation with mixed cultures. My goal at Flat Tail is to explore all aspects of beer fermentation, providing a wide array of house made products to satisfy any and all palates.

Design Element 50x50Logsdon Farmhouse Ales – Hood River, Oregon

Interview with Shilpi Halemane, Head Brewer

PDXBeerGirl Coolships Logsdon Farmhouse Ales Filling
Photo Courtesy of Logsdon Farmhouse Ales

When did you install your coolship, where did you get it, and can you provide a brief description?

It was installed in January of 2015, and was fabricated by Marks Design & Metalworks. It is made of stainless steel, and is 6 ft x 12.5 ft x 14″ inches (depth). We typically brew 10-12bbls of wort to fill it and have some space for foaming.

How often is it used? Is there a particular time of year?

Ideal conditions are when the temperature overnight is below 40 degrees F. The brewing season runs generally from Fall to Late Winter. Because of our elevation and location near Mt. Hood, We get an excessively cold period in the middle of winter, so don’t brew much during January/February, but we do have cool nights extending into the first week or two of May. This allows us to brew a little longer into the year than most spontaneous breweries, but we have to keep an eye on weather conditions.

Did you research the airborne fauna before installing?

Did we try to grow/cultivate some of our natural flora before brewing batches? We did not do that, but just started brewing. We often utilize a mixing tank called a “Horny Tank” (actual term) to homogenize the batch before racking into barrels for fermentation. This tank has had almost every coolship brew ran through it (except recent experimental worts using different malts/brewing procedures), so it is a thoroughly complex playground of microorganisms.  

PDXBeerGirl Coolships Logsdon Farmhouse Ales Filled
Photo Courtesy of Logsdon Farmhouse Ales

There are also differences in the fermentations inoculated in the Fall versus Winter or early Spring when the trees are starting to bloom in the surrounding orchards of the Valley. In the deep Winter we’re getting our inoculant mainly from the dust of the barn, whereas in the fall/spring there is more orchard dust in the air. These can result in more/less acidic beer, or beer with more/less wild yeast character. Blending from different points in the season can bring all the elements together.

In general, the right microorganisms to inoculate these types of beers are present in every brewery. We are lucky to also be located where there is cleaner air than the city, and orchard dust on the wind.

Design Element 50x50McMenamins Edgefield – Troutdale, Oregon

Tour with Nathan Whitney, Head Brewer

PDXBeerGirl Coolships McMenamins Mash Tun

McMenamins’ coolship was installed in 2017 at Edgefield, a previous mash tun used at Olympic Club in Centralia, WA. The equipment became available, so they decided to experiment with it. The batches were small enough (3bbl), that they could be dumped with minimal loss if they turned out poorly. In general, it was an effort to prove themselves capable of making wild ales.

They see the complexity of the area as a unique combination of elements that will add to their beers. On the property are blackberries, a pinot vineyard, and flowing water.

So far, two beers have been made. One was produced in October of 2017, and released in early Summer. The second was produced in February of 2018 and packaged in July.

Design Element 50x50Pfriem Family Brewers – Hood River, Oregon

Interview with Gavin Lord, Head Brewer and Josh Pfriem, Founder

PDXBeerGirl Coolships Pfriem Family Brewers Filling
Photo Courtesy of Pfriem Family Brewers

Was it part of your original business plan to incorporate a coolship and coolship beers?

We’ve been actively planning the installation of a coolship for about three years,” said Josh Pfriem, Brewmaster and co-founder. “We wanted to make sure we were ready, that we’d done our homework and that we could tackle the project with confidence.”

“We plan on installing the coolship and a blending tank in early September. (Gavin Lord, Head Brewer) This will allow us to get comfortable with our set up prior to the start of what we view as our coolship brewing window in November. Our analysis shows that we ought to be able to brew into the coolship from November to early February on an average year. Production will begin soon thereafter, though the much-anticipated coolship beers won’t hit the market for several years.”

What will your coolship look like? (material and form)

Our coolship will be all stainless steel and 30BBL in volume.

PDXBeerGirl Pfriem Family Brewers Coolship
Photo Courtesy of Pfriem Family Brewers

What’s the strategy behind adding one?

I find it refreshing that you’re asking “Why?”. There are several reasons we’ve decided to embark upon what will undoubtedly be a long and hopefully enlightening journey.

The first is flavor. We can taste the difference between “Wild or Spontaneous” beers and those inoculated with a Lab culture. This is not to say that one or the other is better. Indeed, after the incorporation of our coolship we’ll continue to rely upon Lab cultures for many of the mixed culture and barrel aged beers we produce. Rather, the coolship will allow us to add another beautiful and complex color to our palette.

The second is that we feel unbelievably lucky to get to live and brew where we do. We’re nestled between Majestic Mt. Hood and the Mighty Columbia. We’re a stone’s throw from some of the World’s premier Orchards, Vineyards, Farms and Forests. And while we already seek to express this Time and Place through the use of fresh, local fruits, the utilization of Native Microflora represents the ultimate next step in the expression of our unique Terroir.

Finally, as Brewers, we subscribe to the belief that the moment we stop learning is the moment we become obsolete. This industry, and the collective National Palate evolve too quickly for one to stand idly by. The incorporation of the coolship represents the realization of a long term goal for the Brewery, but as Brewers, the Journey is just beginning. We have so much to learn, and we can’t wait to get started.

I could probably go on talking about the coolship all day, but for Brevity’s sake, I’ll stop there.

Something in the air where you are?

“About a year ago, we completed a comparison of Hood River’s climate with that of Brussels, Belgium,” Pfriem said. “What we found was that, beginning in November, the two areas are, climatically speaking, remarkably similar for about four months out of the year. Those months will constitute the main brewing window as far as the coolship is concerned.”

Design Element 50x50Wolf Tree Brewing – South Beach, Oregon

Interview with Joe Hitselberger, Owner & Brewer

PDXBeerGirl Coolships Wolf Tree Brewing Outdoor
Photo Courtesy of Wolf Tree Brewing

When did you install your coolship?

We installed it in the fall of 2016.

Where did you get it?

We came up with a design after researching it a little bit and had a local metal shop build it for us.

Can you provide a brief description (mainly interested in type of material and shape)?

Our coolship is built out of stainless steel. Its capacity is roughly 7bbls, and is rectangular in shape. When it is full, the depth of the liquid is around 9 to 10 inches.

PDXBeerGirl Coolships Wolf Tree Brewing Lean To
Photo Courtesy of Wolf Tree Brewing

How often is it used? Is there a particular time of year?

We try to get about 10 batches brewed with it a year. So far we have only used it in the winter and the spring when we have cooler nights.

Did you research the airborne fauna before installing?

We didn’t, but we felt that it would be a great fit at the brewery. Our brewery is located on a farm, in the middle of the forest a few miles inland from the coast. We felt that we would have pretty good bugs out here and just decided to go for lit.  So far it has worked out really well. This summer was the first time we packaged some of the coolship beer and it turned out great! I hope that we will continue to use it more and more at the brewery grows.