In the first few pages it was pointed out how some yeasts can look similar at the genetic level, but be vastly different. It's possible that one or more of the identified yeasts is wrong, but the same trio has been carried on for over a year.
That first line sounds like something I might have said, in which case it needs a bit of clarification. At a global scale, humans and chimps share ~99% of their DNA [OK, it depends on your definitions, but it works for these purposes] but we are clearly very different.
At the same time, despite that 99% similarity at the species level, and sequence identity between species for a lot of important genes where mutations can be fatal, and >>99% similarity within a species, there are still small bits of the genome which vary so much that CSI can tell whether you or your brother committed the murder.
So whilst "genetically similar but phenotypically different" is an important caveat, you have to say what scale of genetic differences we're talking about. Also, we now have better understanding of the relationships at the genomic level - only since January have we known that T-58 is closely related to Windsor, but the PCR patterns can still be distinguished pretty readily. That gives us a handle on the kind of distinctions we're playing with and our confidence in being able to resolve individual strains.
There's also the non-DNA evidence, inasmuch that we know that small breweries commonly use dry yeasts - cheaper than liquid pitches but still avoids the complications of running your own house yeast. Blending them is a cute twist that gets round the problem of there only being 20-odd strains commonly available in dry form which means a lot of breweries tend to make beer that tastes pretty similar. The nature of how commerce works is that a brewery will tend to use dry yeast from just one company - they could use more than one, but will explore their main supplier's range in the first instance.
There's also the experimental evidence, of contributors here who have brewed with S-04/T-58 blends and found it gives a good approximation to their impression of the TH yeast profile. And ultimately that's what really matters - we're not doing this out of some arcane interest in brewing theory, we're just trying to make better beer. The S-04/T-58 combo works. Whether it is the actual combo used by Treehouse doesn't really matter.
So as a cautious chap, I'd say we're at least 90% confident that they're using S-04 and T-58, and mebbe 75% confident about WB-06 (no disrespect to isomerization - I've done gels that were plenty worse! - I'd just feel happier with a fresh run of that gel ).It's not something to bet the mortgage on, but I'd bet a pint on it.
Others less cautious might say we were 95+% and 90% confident about the identities. But as I say, it doesn't really matter what TH use, what matters is whether we as homebrewers make better beer.
