So I’m aware that the technical difference between lagers and ales are in the way they ferment. Would you expect to see a lager fermenting on the bottom? And what the heck would that look like (imaging foam on the bottom of the carboy, which would be impossible)?
The yeast is throughout the beer in either case. Top fermenters have more at the top, bottom fermenters have more of a yeast concentration at the bottom. It is not a 1 and 0 situation.
I “see” no difference myself. Though due to typically cooler temps you may see less violent krausen with a lager. Also at cooler temps the liquid holds more CO2 so it can take longer to see airlock activity.
For me, with lagers it’s even more important that your temp doesn’t drop. So for example, cool to a couple degrees below your target temp before pitching. Then maybe up to target temp till after most of the fermentation is done, then up to diacetyl rest, but avoid up and down. Until it’s totally done then you can crash if you wish.
A lot of the krausen is just beer foam- like what you’d seen on top of your beer.
If you want to see what a serious top crop looks like try a batch with Wyeast 1318 London Ale III.
How do they know where the yeast are doing their thing in tge fermentor? Reminds me of an old 60s movie where they shrunk the scientists and they injected them and their tiny submarine into some dude.
If you re using a carboy sometimes you can actually see during the initial growth stage a haze of yeast either at the top or the bottom. But once fermentation kicks off you can’t tell.
I think that there is fermentation throughout with both types of yeast, but that the lager yeast are still chugging away for quite a while longer after the krausen falls - not necessarily for weeks, but generally speaking for a bit longer. A properly pitched lager may keep working for weeks to clean up, whereas a properly pitched ale could be done in a few short days. D- rest, pressure and warming at the end of preliminary activity (krausen fall) all speed up the process for lagers, of course…and this is generalizing in a major way, as I have used ale yeasts that take their time and stall if not coaxed to finish. I bet someone can say more regarding the technical biological differences between the saccharomyces strains…and there is the Yeast book to reference here.
The terms “top fermenting” and “bottom fermenting” are bogus. All yeast ferments throughout the beer – top, bottom, middle, everywhere. Lager fermentations take longer to finish fermenting, after the krausen has fallen back in, so this might be the origin of the terms. However in the first week or so of fermentation, lagers and ales look basically identical.
So what is the difference? Other then I can’t drink most lagers.
Well, this is a quote from Wyeast’s website technical section, yeast fundamentals page
" Ale and lager yeasts are currently both classified as Saccharomyces cerevisiae"
I don’t believe it. If true, that would be revolutionary information. Millions of people have been taught that lager yeast is a different species from ale yeast. Related, but different species. Kind of like the difference between chimpanzees and bonobos (notice I did not say humans).
Lager yeasts are capable of eating a couple more kinds of sugars than ale yeasts, and remain more active at colder temperatures than ale yeasts. There’s probably 50 different types of sugar, and lager yeast can ferment a few more than ale yeast. That’s my understanding of the primary differences between species.
Hardly revolutionary in biology to reclassify organisms - either deciding that two species are the same or splitting strains into distinct species. It happens all the time. Just look at dogs if you want to see the diversity that can come from a single species. Or humans - some can’t digest certain things (like lactose) and some can.
So lactose-intolerant folks are the ale yeast of humans?
“In today’s news, FLBrewer discovered there is no difference between lagers and ales…craft beer fans are outraged”
I guess so
From wikipedia:
[quote]As S. pastorianus is a hybrid of Saccharomyces bayanus (or, as recently proposed, Saccharomyces eubayanus [3]) and Saccharomyces cerevisiae, finding a degree of phenotypic and genomic similarity between the two species is not surprising.[4] The hybrid nature of S. pastorianus also explains the genome size, which is up to 60% larger than that of S. cerevisiae, as it includes large parts of the two genomes.[5] There is growing evidence, however, that S. pastorianus has inherited most of its genetic material from S. bayanus.[5] Indeed the mitochondrial DNA[6] and ribosomal DNA[5] of S. pastorianus appear to be derived from S. bayanus rather than S. cerevisiae.
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Phew! that clears it up. :o
to me the big difference is temperature tolerances. while you can ferment an ale or a lager yeast at say 65 you can ferment a lager yeast at 45 and the vast majority of ale yeasts would not be able to be active at those temps. As I understand the current genetic info on these yeasts the new world S. eubayanus contains those genes conferring the abilitity to be active at a lower temps.
The difference is the genetics of the yeast.