Fining, Filtering, Or Not

At Triptych, we have beers on the menu that have been filtered. Many of our lagers for instance are run through a coarse filter with a nominal particle retention rating of 6-12 microns. In our four unit filter housing there is around 216 square feet of filter surface area that retains yeast, other particles, and proteins that prevent a beer from being completely clear. Other beers on the menu at Triptych have been fined, that means we’ve introduced a fining agent to encourage sedimentation of the yeast and proteins that contribute to haze in a beer. And still other beers at Triptych receive no filtering or fining treatment at all. How do we determine what process we should use on which beers?

For me, it starts during the recipe design phase. I usually have an aesthetic in mind for a beer when I am pondering what sort of flavor profile we are pursuing. If I am designing a lager, 99% of the time, I picture that crystal clear glass of lager sitting on a table with tiny beads of condensation forming on the glass while you savor each sip. When we brew lagers, the cold aging process (i.e. lagering) removes most of the yeast and haze from the beer. And if we waited even longer than our standard 6 week process, eventually all of it would fall out of solution (see Wandervogel: Mosaic, started on tap fairly hazy, now its very clear). But alas, more beer must be brewed, so sometimes we will send a lager through the filter so that it can meet that mind eye’s expectation of brilliantly clear but also fit inside the timelines of a busy production brewery. The filter is the most aggressive tool at our disposal to clear beer and it removes yeast, proteins, hops, a slice of everything that is above that nominal 12 micron rating. So we tend to only employ it on beers that we expect to be brilliantly clear which are usually beers that don’t have a ton of yeast derived aromatics or dry-hop aroma/flavor.

Fining is our second method for clearing up a beer. Fining describes the process of adding a processing aide to a beer, usually of a positively charged nature to help speed up sedimentation and flocculation of the yeast. Brewers yeast, at beer pH, after fermentation, is typically of a negative charge and so when you introduce a positively charged colloidal solution to the beer, you attract the yeast cells and as more and more of them stick together, they fall out of the beer faster (if you’ve been on a Triptych tour, we talk about this process and about Stoke’s law which describes that the bigger a particle is , the faster it falls out of solution). In the old days of English brewing, a common fining agent was Isinglass. Made of dried swim bladders of fish, Isinglass proved to be a reliable way to compact yeast, hops, and protein to make a clear pint of English cask beer. Gelatin is another animal derived product which is still fairly commonly used in American craft brewing. At Triptych, when we fine a beer, we use a product derived from silica (i.e. quartz sand) called Biofine. Completely vegan, inert, and effective, we introduce Biofine early enough in the process and at a small enough dosage level that it does not carry forward into the packaged beer. We often utilize Biofine on beers that have historically been clear at Triptych, Dirty Hippy, Little Secret, Galloping Ghost, beers that we anticipate the filtering process having a negative effect on.

Make no mistake though, fining or filtering, or even just waiting 6-8 weeks for a beer to naturally clear, changes the flavor profile of the beer. For some of our beers this is appropriate, but for aggressively fruited sours or aggressively dry-hopped New England style IPAs, we find au naturel to be best for the beer. So whether the Triptych beer in your glass is brilliantly clear, somewhat hazy or completely opaque, you can be sure that we made a conscious decision for the best of the beer.

In the picture below… on the left is a batch of Little Secret from February and pictured on the right is an upcoming, special edition batch from March featuring Strata hops. One batch is fined, one batch isn’t, can you see which is which?

Hop Creep!

Let’s explore a phenomena that has challenged Triptych in the past and continues to sometimes present issues for us, it’s called Hop Creep. But first, let’s recap how beer is made. If you’ve had the chance to attend one of our brewery tours (quick plug, I’m giving the tour this Saturday!), some of this will sound familiar. To make beer at Triptych, we take grain that has been malted by a maltster, soak it in some hot water, strain the liquid, boil it, add hops, cool it, add yeast, wait a bit, and boom! We have beer. Let’s zoom in on what “malted” actually means. Malted grain is germinated under controlled conditions to develop enzymes inside the grain kernel. In the brewing process, the introduction of hot water activates these enzymes and converts the starch in the grain kernel to sugar and that sugar later becomes alcohol and fizz in the beer via the magic of fermentation. Enzymes are really neat. They’re basically a special kind of protein that work as a catalyst for reactions, like the conversion of starch to sugar. Enzymes never get used up and the only real way to deactivate them is with heat, like the heat that comes during the brewing process. But did you know that hops also contain some of the same enzymes that malted barley has? And that is where our challenge begins.

Hop creep is a modern name for something that has existed since the dawn of dry-hopping beer. In 1941, British brewing literature pointed out the phenomenon where otherwise stable casks of ale would continue to ferment after hops were introduced. But the interesting intersection and popularity of beers that contain a lot of hops (i.e. 2+ ounces per gallon of beer), that are also unfiltered (so there is still some amount of viable yeast cells present) have brought hop creep to the forefront again. During the brewing process, we manipulate several variables with the goal of creating a specific mix of different sugars and proteins. And normally, the boiling part of the beer making process deactivates any enzymes present so that our mix of sugars and proteins is preserved. But when we dry hop, a new batch of enzymes are hitching a ride into our beer. And enzymes don’t discriminate, they take the complicated sugars that were impossible for the yeast to digest and they start simplifying them into a form that the yeast can once again consume. This secondary fermentation causes the beer to change. It changes the balance of the beer, it changes the alcohol content, and unfortunately, if the beer is in a container, it can rupture the container. So what can we do to try and prevent hop creep?

We could pasteurize our beer. Unfortunately, we currently lack the equipment to make this happen, but for an investment around $100k, we could definitely do it. But... pasteurizing is also not necessarily appropriate for every style of beer and existing brands would need to be modified to account for the changes pasteurization brings.

We could add lactose to every beer! The enzymes in hops are unable to act on lactose so we could use lactose to ensure our balance stays as intended… of course, lactose and I don’t have a great history together so that would probably not be a great solution either.

We could filter or aggressively fine our beer. Without the yeast in the beer, even if enzymes modify the sugar profile, there’s no yeast there to ferment the new sugars and this particular problem has been averted. We have several brands of beer at Triptych that are filtered/fined so that minimal yeast in the final beer, but this approach isn’t appropriate for every style of beer that we produce.

Another way we try and prevent hop creep at Triptych is through carefully monitoring fermentation progress and keeping detailed statistics about every batch. With enough data, we can time the addition of dry hops and the packaging of the beer to try and ensure that the majority of the secondary, hop induced fermentation happens in our fermentation tank and not in a can of beer. But some variables that affect the speed and veracity of this process are still out of our control. Hops will contain varying amounts of soluble enzymes depending on where they were grown and how they were handled after harvest. So one brand of beer that may have never exhibited any symptoms of hop creep may start showing it as hops from a new harvest year roll in.

The final way that we currently try to address hop creep at Triptych is by keeping our beer cold at all times. Low temperatures will significantly slow down the yeast so that any activity is very minimal. We may seem militant at times about our stance regarding cold beer and hop creep is just one of the many reasons why.

Fortunately this isn’t the last word on what we’re doing to try and address hop creep. We’re constantly experimenting with new techniques to mitigate this interesting phenomenon without compromising the characteristics that make our juicy, hazy, hop forward beers enjoyable.