The K-97 Yeast Mystery

[rich_lamb]

When I've posted in the past suggesting that SafWheat K-97 is a good ESTERY yeast for various wheat beers, I've had varying replies to suggest it's actually a clean german ale yeast, more suited to Kolsch or whatever.

So I'm a bit confused, as I've now used it twice myself (and observed it used by a mate once) and had the same results:
1) Characteristic very long lag time of 36-48 hours, though a healthy krausen builds during this time
2) Truckloads of esters. Not the more refined aromas and flavours you might prefer in a traditional heffe, but lots of banana and particularly strong bubblegum.

I use this yeast for a specialty honey wheat recipe of mine, and this character is actually what I'm after in this case so I guess it's a win

So, perhaps this yeast is a doppleganger? Does it ferment clean at low temperatures or something? The docco is a little open to interpretation. Can a yeast act differently with different wort fermentability?

FYI: My recipe is just pils malt, wheat malt and maybe 20% honey. I ferment normally at 20, but the last one was getting a bit carried away and was closer to 21-22.

cheers
B&T

 

[yardy]

i use it in the house wheat/rye beer, usually @ 17*C, nowhere near the lag you have though, are you aerating/oxygenating ?

no banana or bubblegum here either, due to temp i suppose, i really like this yeast with the Rye, then again i like anything with Rye.......

cheers
yardy

 

[Ross]

Straight from the Fermentis site:

K-97 A German ale yeast selected for its ability to form a large firm head when fermenting. This top cropping ale yeast is suitable for top fermented beers with low esters levels and can be used for Belgian type wheat beers. Sedimentation: low. Final gravity: low.

I actually used K-97 for the 1st time last month & made an Alt. The beer within 2 weeks of being in the keg is super clean with not a hint of banana or bubblegum.

I have no idea how you are getting that character, as I've tasted several brews from other brewers & they too have been very clean - very strange :huh:

Cheers Ross

 

[warrenlw63]

I have no idea how you are getting that character, as I've tasted several brews from other brewers & they too have been very clean - very strange :huh:

Cheers Ross

Sounds like a symptom of underpitching to me. The long lag time sort of underlines this too. :unsure:

Warren -

 

[therook]

Straight from the Fermentis site:

K-97 A German ale yeast selected for its ability to form a large firm head when fermenting. This top cropping ale yeast is suitable for top fermented beers with low esters levels and can be used for Belgian type wheat beers. Sedimentation: low. Final gravity: low.

I actually used K-97 for the 1st time last month & made an Alt. The beer within 2 weeks of being in the keg is super clean with not a hint of banana or bubblegum.

I have no idea how you are getting that character, as I've tasted several brews from other brewers & they too have been very clean - very strange :huh:

Cheers Ross

Hey Ross, how did the K-97 compare to the Nottingham in the ALT?

Rook

 

[ausdb]

I actually used K-97 for the 1st time last month & made an Alt. The beer within 2 weeks of being in the keg is super clean with not a hint of banana or bubblegum.

+1
I am probably one of the ones saying it is a like a Kolsch yeast as I have found it works well with "Koslch" style beers and does not seem to be a lot different to WY 1007. What temp are you fermenting at?

 

[Ross]

A lot of brewers Australia wide seem to have had trouble in the past with long lag times using K-97.
I'm under the firm belief that this is due to a batch of yeast that has had its viabillity knocked out of it, somewhere in its travels, or maybe it's just not as tolerant to poor storage. My brew kicked off in normal time with no problems.

Make sure your K-97 is well within it's use by date & comes from someone that looks after their yeast.


Cheers Ross

 

[Cortez The Killer]

I fermented K-97 at 21-22*C and got banana flavours with the following

57.4 3.17 kg. JW Malted Wheat Australia 1.028
34.0 1.88 kg. JW Export Pilsner Australia 1.016
4.3 0.23 kg. Cara-Pils Dextrine Malt 1.002
4.3 0.23 kg. Melanoidin Malt 1.002

Came out a very nice beer - though definitely not a wheat beer by any means

I've still got another pack of this yeast in the fridge and am not too sure what to make with it

Cheers

 

[clay]

I used K97 awhile ago in a hefe and while I did get some flavours you would expect from a hefe they were quite muted. A bit of clove and a bit of banana. One of my mates did comment that all he could taste was banana. Would be happy to use it in an Alt if is performed like 1007

clay

 

[rich_lamb]

Yeah, the symptoms do sound like underpitching, though I generally wouldn't expect this with 11g of dry yeast correctly rehydrated into an 18 litre batch of about 1.052. I oxygenate pretty well and haven't had issues elsewhere.
The long lag isn't necessarily a bad thing and may be characteristic - it certainly goes off like a rocket after the growth phase!

As suggested, it could have lost some of it's viability - I don't still have the packet though I'll definitely check next time. I acquired it from a reputable HBS who take yeast handling seriously, for what it's worth. When I use dry yeasts I usually notice the yeast goes readily into suspension when hydrated (in 250ml @ 28-30 deg). Most of this one just wanted to settle - maybe it was a bit tired and emotional.

The Fermentis data doesn't say much about the flavour profile other than "low esters" - certainly not what I got. It's a bit misleading calling it SafWheat if it's intended for clean German Ales like Alt/Kolsch. I guess Hefe is technically a German ale

I guess I'm now curious if there could be a packaging or naming issue. Maybe what I'm using isn't the same as what's available elsewhere? ... as I've now seen the same thing three times.
Could be a moot question: I'm happy with what it does, and don't want to brew a Kolsch

 

[yardy]

I've still got another pack of this yeast in the fridge and am not too sure what to make with it

Cheers

this one i like,

48 % Pale
28 % Wheat
16 % Rye
8 % Vienna or Munich
K-97 @ 17*C.
Hersbrucker & Northern Brewer to about 28 / 30 IBU

a bit of Pale Choc for colour if you're that way inclined.

cheers
yardy

 

[joecast]

a timely topic for me as i've got some in primary now. and its a kolsch!

pitched at about 16C and took about 24hrs to start bubbling. been going now for 3 days and has slowly warmed to about 20C. anyway, im hoping the cooler pitching temp keeps the esters from getting too strong. i'll know in a couple of weeks, or more if i cc for a while.
joe

 

[Ross]

The Fermentis data doesn't say much about the flavour profile other than "low esters" - certainly not what I got. It's a bit misleading calling it SafWheat if it's intended for clean German Ales like Alt/Kolsch. I guess Hefe is technically a German ale

Where do you get safwheat from :unsure: Fermentis refer to it as Safale.

cheers ross

 

[Simon W]

Ross, on an old pack I've got in the fridge:
Bintani stick-on label: Safale/Wheat K-97
Then printed directly onto the mylar(?) bag: Wheat/Ale Yeast K-97 11.5g 4266

Dunno who did the bagging, probably Bintani

 

[bconnery]

Where do you get safwheat from :unsure: Fermentis refer to it as Safale.

cheers ross

HBS in Australia have been referring to it as safwheat for years. Fermentis may never have, and I don't know when it started exactly but I've seen it done so the whole time I've been brewing...
Try a quick google search for safwheat and check out the first link that comes up (at least in mine...)
A major known HBS has it listed as exactly that...

I agree that it isn't right, but it happens...

 

[therook]

Hey Ross, how did the K-97 compare to the Nottingham in the ALT?

Rook

Ross,

You may have missed my post, how did the 2 compare.

Rook

 

[chimera]

Used K-97 quite a few times in the past, and while I do have a bit of a problem with fermentation temperatures creeping high at times, I have fermented K'97 17-18C and still found it to be characteristically banana estery and long lagging.

My best experiences with this yeast were using it with lower wheat content and bottle conditioning for quite some months for the esters to calm down.

Agree with Ross - maybe a bad batch, but it must have been a HUGH batch given that I bought the yeast from more than one HBS over 14-18 months.

I suppose it's like all dried yeasts, once you use them a few times you get used to their particular characteristics, and there are things to like and dislike about them all. This time last year I thought S-23 was useless crap, but my winter lagers have been some of the cleanest beer i've made, and thoroughly bested the ones made with W34/70 over the same period

 

[Ross]

Ross,

You may have missed my post, how did the 2 compare.

Rook

Hi mate, yes sorry I did miss.

The K-97 brew had a taste i wasn't too happy about when first kegged; hard to describe, but basically a strong yeasty background taste, compared to the Nottingham that can throw up quite a dusty profile. That said - 4 weeks in the keg & it's tasting great.
The Nottingham attenuates better so would probably be my pick for this style, but I'll leave the final verdict for when this ones had a few months aging, as it's improving all the time.

cheers Ross