skortjorkson
I Eat Magic Plants
Hello!
To begin with, I would like to mention the package and marketing. I originally purchased K-97 online without being able to read the package, and it was being marketed as 'German Ale'-- you can imagine my surprise when it came and the text read "German ale yeast selected for fine Belgian wheat beers characterized by a good length on the palate." What the heck? Is it German, or Belgian, or...? "Length on the palate"? What's going on here? Well, never fear, intrepid reader, I am here, with the help of experience, to unravel this mystery for you.
This yeast has some unique traits, but given the description I can understand why it may be often overlooked. It's a fairly neutral, top-fermenting, cold-adapted strain. Attenuation is fairly low, and alcohol tolerance also seems low. At first taste it seems like a troublesome alternative to US-05 or Nottingham Ale, and I wouldn't choose it for an altbier or any yeast-driven Belgian recipe. So what good is this strain, which has captured my heart? The secret lies in its other fermentation characteristics.
Firstly, this yeast is PERFECT for an open fermentor. It produces a more resilient krauesen than any other strain I have worked with to date. I have been strictly using an open fermentor for some time, and often my fear of oxygen or contamination leads me to rack a beer to secondary as soon as the bared surface of the beer shows through, even though it's early. K-97, on the other hand, keeps a protective skin of yeast on the surface even while the beer underneath has finished fermenting and mostly clarified. This also allows the brewer to EASILY top-harvest yeast for the next batch without worrying about trub or dead yeast-- it's all at the bottom-- and due to the krauesen's longevity one can take one's time in doing so. I understand how a resilient krauesen is a tiny nightmare for anyone working with an enclosed fermentor, but this yeast was bred for and excels in the open. My culture is currently on its 8th generation and I have yet to encounter any kind of mutation or contamination.
Second: length on the palate. Everyone familiar with so-called brown yeast? This is the collection of hop oxides which typically ferment out in the form of a brown, bitter resin which floats to the top of the krauesen, sticks to the sides of your fermentor and is hard to clean. The process of these hop compounds fermenting out is one element of what's responsible for the difference in harsh bitterness between wort and finished beer, with most yeasts. K-97, however, as far as I can tell, does not ferment out the brown yeast, instead leaving these hop compounds in the beer. Ale made with K-97 has a really bracing bitterness which could be interpreted as 'unrefined hop flavor', but I consider to be greater hop utilization. One must use a gentle hand when adding bittering hops to a K-97 brew; it's easy to make something unpalatably bitter when experimenting with early-boil hop additions. However, I find it a greater advantage in making hoppy beers than a disadvantage, as K-97 modifies (or moderates) the hop character less than other yeasts. It also makes the fermentor easier to clean!
Temperature and fermentation schedule: I found this yeast to perform well in a wide temperature range from around 45-65F. At the lower end of the spectrum, 45-50F or below, it slows down and attentuation suffers. One batch I had froze partially and the yeast was still visibly active, though, so it is quite resilient. At the higher end, 65F, fermention produced a strong banana aroma, and the finished beer had a strong but delicate pear aroma (no banana aroma or flavor though!). My typical fermentation schedule has been to pitch the yeast at around 65F and ferment for 10 days at 55F. Higher temps it took less time, lower temps more. I have then been harvesting all of the yeast from the top and racking to secondary, then aging for 2 weeks at 40F before kegging.
NOTE: The yeast itself smells like sourdough, especially at the end of fermentation. It may put off a funky smell towards the end, but this is not necessarily indicative of an infection!
Clarity and sedimentation: Once fermention is complete, this yeast settles fairly quickly compared to other low-flocculating German and Belgian yeasts I have used. The resulting sediment is not very compact, but it also doesn't stay in suspension long if roused.
That being said, K-97 produces a VERY clear beer if provided with a well-mashed and well-lautered wort! Absolutely crystal clear if treated properly.
Suggested uses: K-97 is perfect for producing beer in the European sense of the word-- biere, as opposed to ale. The ideal recipe for K-97 is something light-bodied, light-colored, and brilliant with a refreshing bitterness. Session IPAs, blondes, wheats, or Grätzers are my best suggestions. Potentially suitable for Kölsch, although I suspect the attenuation is too low for a pseudo-Pils.
It makes a decent West Coast IPA, and passable darker ales (reds, browns, etc), but not spectacular; I would recommend WLP1007 instead for an actual altbier, or any malt-driven ale. I did try making a stronger black beer with K-97 which has been aging for 2 months already and is struggling to come together. This yeast's strong suit is delicacy!
Hence, perhaps, the difficulty of putting it into a traditional homebrew yeast family. K-97, I would argue, is an overlooked relic of the hoppenbier tradition that so upset English sensibilities in the 16th and 17th centuries. This is for lowland Continental ale, the once-everyday drink of the area sandwiched between the spicy yeasts of French-speaking Belgium and the better-defined North German brewing tradition: known as Lower Lorraine, Brabant, the lower Rhineland, depending on who you ask. I would suspect its ancestors once filled a role in the larger region which lager now occupies.
Regardless, I highly recommend giving it a try, as in the right brewing conditions K-97 can really shine.
Cheers!
To begin with, I would like to mention the package and marketing. I originally purchased K-97 online without being able to read the package, and it was being marketed as 'German Ale'-- you can imagine my surprise when it came and the text read "German ale yeast selected for fine Belgian wheat beers characterized by a good length on the palate." What the heck? Is it German, or Belgian, or...? "Length on the palate"? What's going on here? Well, never fear, intrepid reader, I am here, with the help of experience, to unravel this mystery for you.
This yeast has some unique traits, but given the description I can understand why it may be often overlooked. It's a fairly neutral, top-fermenting, cold-adapted strain. Attenuation is fairly low, and alcohol tolerance also seems low. At first taste it seems like a troublesome alternative to US-05 or Nottingham Ale, and I wouldn't choose it for an altbier or any yeast-driven Belgian recipe. So what good is this strain, which has captured my heart? The secret lies in its other fermentation characteristics.
Firstly, this yeast is PERFECT for an open fermentor. It produces a more resilient krauesen than any other strain I have worked with to date. I have been strictly using an open fermentor for some time, and often my fear of oxygen or contamination leads me to rack a beer to secondary as soon as the bared surface of the beer shows through, even though it's early. K-97, on the other hand, keeps a protective skin of yeast on the surface even while the beer underneath has finished fermenting and mostly clarified. This also allows the brewer to EASILY top-harvest yeast for the next batch without worrying about trub or dead yeast-- it's all at the bottom-- and due to the krauesen's longevity one can take one's time in doing so. I understand how a resilient krauesen is a tiny nightmare for anyone working with an enclosed fermentor, but this yeast was bred for and excels in the open. My culture is currently on its 8th generation and I have yet to encounter any kind of mutation or contamination.
Second: length on the palate. Everyone familiar with so-called brown yeast? This is the collection of hop oxides which typically ferment out in the form of a brown, bitter resin which floats to the top of the krauesen, sticks to the sides of your fermentor and is hard to clean. The process of these hop compounds fermenting out is one element of what's responsible for the difference in harsh bitterness between wort and finished beer, with most yeasts. K-97, however, as far as I can tell, does not ferment out the brown yeast, instead leaving these hop compounds in the beer. Ale made with K-97 has a really bracing bitterness which could be interpreted as 'unrefined hop flavor', but I consider to be greater hop utilization. One must use a gentle hand when adding bittering hops to a K-97 brew; it's easy to make something unpalatably bitter when experimenting with early-boil hop additions. However, I find it a greater advantage in making hoppy beers than a disadvantage, as K-97 modifies (or moderates) the hop character less than other yeasts. It also makes the fermentor easier to clean!
Temperature and fermentation schedule: I found this yeast to perform well in a wide temperature range from around 45-65F. At the lower end of the spectrum, 45-50F or below, it slows down and attentuation suffers. One batch I had froze partially and the yeast was still visibly active, though, so it is quite resilient. At the higher end, 65F, fermention produced a strong banana aroma, and the finished beer had a strong but delicate pear aroma (no banana aroma or flavor though!). My typical fermentation schedule has been to pitch the yeast at around 65F and ferment for 10 days at 55F. Higher temps it took less time, lower temps more. I have then been harvesting all of the yeast from the top and racking to secondary, then aging for 2 weeks at 40F before kegging.
NOTE: The yeast itself smells like sourdough, especially at the end of fermentation. It may put off a funky smell towards the end, but this is not necessarily indicative of an infection!
Clarity and sedimentation: Once fermention is complete, this yeast settles fairly quickly compared to other low-flocculating German and Belgian yeasts I have used. The resulting sediment is not very compact, but it also doesn't stay in suspension long if roused.
That being said, K-97 produces a VERY clear beer if provided with a well-mashed and well-lautered wort! Absolutely crystal clear if treated properly.
Suggested uses: K-97 is perfect for producing beer in the European sense of the word-- biere, as opposed to ale. The ideal recipe for K-97 is something light-bodied, light-colored, and brilliant with a refreshing bitterness. Session IPAs, blondes, wheats, or Grätzers are my best suggestions. Potentially suitable for Kölsch, although I suspect the attenuation is too low for a pseudo-Pils.
It makes a decent West Coast IPA, and passable darker ales (reds, browns, etc), but not spectacular; I would recommend WLP1007 instead for an actual altbier, or any malt-driven ale. I did try making a stronger black beer with K-97 which has been aging for 2 months already and is struggling to come together. This yeast's strong suit is delicacy!
Hence, perhaps, the difficulty of putting it into a traditional homebrew yeast family. K-97, I would argue, is an overlooked relic of the hoppenbier tradition that so upset English sensibilities in the 16th and 17th centuries. This is for lowland Continental ale, the once-everyday drink of the area sandwiched between the spicy yeasts of French-speaking Belgium and the better-defined North German brewing tradition: known as Lower Lorraine, Brabant, the lower Rhineland, depending on who you ask. I would suspect its ancestors once filled a role in the larger region which lager now occupies.
Regardless, I highly recommend giving it a try, as in the right brewing conditions K-97 can really shine.
Cheers!
