It’s a purely semantic discussion. If it looks like a lager, tastes like a lager and quacks like a lager, but has been made with ale yeast, is it a lager?
In my opinion, no. That’s why this whole discussion, as rabeb25 is questioning, seems to be just to kill time. Bet if you ask any German brewer they’ll tell you immediately that, no, it’s not a lager unless it’s made with lager yeast.
No.
We’re on the internet, thus by definition we are killing time, no?
Yes, I suppose so. But we’re also here, on this forum especially, to learn and discuss. There are topics worth discussing, then there are those that we discuss just to kill time, I feel. The “flame out/knock out” was an example of frivolity. This one is only slightly less frivolous. I feel like the answer is pretty obvious - a lager is a lager because of the yeast. There are lagers that aren’t lagered - zoiglbier, zwicklbier, kellerbier…
It’s just one of those things where the yeast defines the beer, regardless of similarity to other beers with different yeasts. As I stated earlier, hefe = hefe yeast, Belgian = Belgian yeast, etc.
But I suppose by that logic, this topic is a learning topic…
I am of the opposite mind, a lager is a lager because it was cold stored. Cold storage can change the flavor profile of a beer dramatically.
Genomics is rapidly showing us that classifying a beer based purely on the yeast species employed is not the best choice, especially when we discover that an older species classification turns out to be wrong. There are top fermenting and bottom fermenting S. cerevisiae strains.
With that said, what distinguishes S. pastorianus from a cold tolerant S. cerevisiae strain? I used to believe that it was sulfur production. However, that belief was put to rest after using the ACME production strain. Can it be the ability to reduce the disaccharide melibiose to glucose and galactose?
Sorry if I had started a dumb topic. That was not my intention. I guess the only prerequisite for a lager is lager yeast. I suppose temp doesn’t matter.
Not dumb at all. It’s a good question to debate.
Sorry, man, didn’t mean to offend, directly, anyway. I just thought it seemed like a fairly obvious answer. As a brewer who brews mostly lagers, I guess I’m a bit biased? It would seem Mark has a more scientific answer, even though I don’t agree with the cold storage argument. Maybe he didn’t read my post about Zwicklbier, zoiglbier, kellerbier, etc. Those beers aren’t lagered for long periods of time, although kellerbier is longer than the other two, but still…it’s typically still cloudy and young. You think Germans call those lagers? You bet they do. And by that same logic, altbier is typically lagered for long periods, but they don’t call those lagers, same for Kolsch.
Any beer can be fined and dropped bright or filtered, making it look like a lager with very little time in cold storage. Does this make it not a lager since it isn’t being stored cold for long periods? Still think that’s not good enough of an argument.
However, the term lager was used long before German brewers even knew that S. pastorianus existed.
Furthermore, if we dissect the S. pastorianus species, we discover two very different families of yeast stains. The Saaz family contains one set of S. cerevisiae chromosomes and two sets of S. bayanus chromosomes whereas the Frohberg family contains two sets of S. cerevisiae and two sets of S. bayanus chromosomes. Carlsberg Bottom Yeast No. 1 is the most popular Saaz strain (Wyeast Danish Lager descends from this strain) whereas Weihenstephen W-34/70 is the most popular Frohberg yeast. Which one of these families contains the true lager strains?
Genetic sequencing is rapidly changing taxonomies. What we will learn in the next decade will probably turn what know today on its head.
No offense taken.
I guess I was looking past or not considering the most obvious answers. I think the answer to my question is that you can make an ale that will pass off as a lager but it isn’t a real ‘lager’. I already knew this but again was looking past the most direct answer. It may win first place against real lagers but it is an imposter. In simpler terms, it all comes down to tradition. A traditional German pils isn’t going to use American two row, etc…
My take away is that there is an argument for tradition vs. impression.
Tradition is just doing something the way it has always been done. If you stuck to tradition, you wouldn’t have west coast IPAs. You’d only have English IPAs.
Not too long ago people would tell you that you absolutely need to ferment your lagers cold. Marshall’s lager fermentation schedule puts the lie to that.
If you submit a beer to a BJCP comp as a lager and it wins, it’s a lager to me because it meets all of the required stylistic characteristics (assuming the judges know what their doing, of course).
No one who’s tasting it knows what yeast you used unless you tell them.
I’d love to see a native German speaker weigh in, what with “lagern” meaning “to store” and all.
Not native German speaker but close. Would that count?
Close enough for me, Leos!
I am in the opinion that me as a brewer, I am making a beer and I use yeast to my advantage.
I can package lager in two weeks and it taste as good or even better then someone’s else 6 week beer.
Who said that Kolsh has to be fermented with XYZ yeast or Scottish Ale with ABC yeast and if I do not use those yeasts then my beers are not Kolsh → Scottish.
I can make those beers with single strain of yeast. Yes I can not make hefe with it but anything else is a fair game.
So pick the yeast strain that you like and learn all you can know about it. Make different beers. Push it out of yeast mfg specs to see what it can really do.
It took me 5 years and 270 batches but it can be done. Go for it.
I just remembered from 20 years ago, while studying for the BJCP test, that the difference between lager and ale yeasts is that lager yeast can ferment rafinose. I have no idea what rafinose is and I don’t believe that this should be the defining attribute, but it used to be part of the definition.
The sugar that truly distinguishes S. cerevisiae from S. pastorianus is the disaccharide melibiose (one molecule of galactose bound to one molecule of glucose via a glycosidic bond). S. cerevisiae strains can metabolize raffinose to a degree just as they can metabolize the trisaccharide maltotriose to a degree. I am unaware of a single brewing S. cerevisiae strain that can metabolize melibiose.
NCYC 396 is Carlsberg Bottom Yeast No. 1 ( a.k.a. Unterhefe Nr. I, which was the world’s first pure lager culture)
Glucose: +
Galactose: +
Sucrose: +
Maltose: +
Cellobiose: Unknown
Trehalose: Unknown
Lactose: -
Melibiose: +
Raffinose: +
Melizitose: Unknown
Inulin: Unknown
Soluble Starch: -
Xylose: Unknown
A M D Glucoside: Unknown
NCYC 240 is the Taylor Walker strain (Taylor Walker was a famous London Porter Brewer)
Glucose: +
Galactose: +
Sucrose: +
Maltose: +
Cellobiose: -
Trehalose: -
Lactose: -
Melibiose: -
Raffinose: +
Melizitose: +
Inulin: -
Soluble Starch: -
Xylose: Unknown
A M D Glucoside: +
- = metabolizes
- = does not metabolize
To perhaps add another wrinkle to the discussion is that prior to industrial refrigeration and yeast strain isolation it is thought that German brewers (and likely others) brewed with mixed fermentation cultures that would bottom ferment in cold months and top ferment in warmer months. These beers were lagered and sold continuously as the same style of beer. Did these beers go from being a lager to not a lager although always lagered?
Maybe everyone else brewed, but the Germans didn’t brew in the warmer months for that reason - it was too warm to ferment their lager yeast strains.
I think we know what lagering a beer is, but I don’t think that is THE thing that defines a true lager. I think it is simple enough an answer to point towards yeast.
And I also think Mark is making all this stuff up. Galactose? That some kind of inter-galactic sugar? 
Kidding of course.