Once you go over 16% or so alcohol, no cell will grow in it. That’s why alcohol above that is distilled: the alcohol starts inactivating the yeast. Just make sure it’s pasteurized to begin with (or good source control) and it’ll stay clean.

Something acts like the surfactant to keep it from separating. Probably not mustard like in a salad dressing :).

Putting on my pedantic home brewer cap: The 16% number seems a bit low. I believe there are champagne yeasts that will ferment up to 18%, and specialized "turbo" yeasts designed for fermenting high-abv washes for distilling will go up to 20%.

I can absolutely agree on the turbo yeast part. I have fermented some apples with turbo yeast and they were able to bring it up to about 21% (but with added sugar).

I just tested a turbo yeast sugar wash I have and it's sitting at exactly 21%

Dare I ask why you happen to have turbo yeast sugar wash lying around?

For making neutral spirits as the basis for gin

In my uni days a flatmate made "wine" like this, surprisingly drinkable with a mixer.

How "recent" are the developments of those turbo yeasts though? I wouldn't be surprised we figured out how to create those only in the last century using modern scientific insights.

It was popular to study fermentation, because nobody knew how it worked. Anton van Leeuwenhoek (the "inventor" of the microscope [0] around 1670) was the first person who saw yeast cells, but nobody knew what it was. In 1880s people realized what yeast is and that it was behind fermentation. Around 1900 breweries began using (their) specific yeast string. Yeast was the first eukaryote which genome was completly sequenced, in 1996. So, yes, research in yeast is relativly modern.

If you are interested in this topic, I can recommend the book "Proof: The Science of Booze" [1] which has a chapter on yeast and a following one on fermenation.

[0] https://en.wikipedia.org/wiki/Antonie_van_Leeuwenhoek

[1] https://www.goodreads.com/book/show/18222694-proof

I am curious actually, thanks for the info!

What does that matter when they're replying to "Once you go over 16% or so alcohol, no cell will grow in it. That’s why alcohol above that is distilled"?

Because it is quite common for common knowledge to be outdated for decades. Even among professionals, let alone the general public.

I've definitely seen (or felt) a separated bottle of Bailey's before. My uncle had one that sat in his liquor cabinet for over a year. When I tried to pour it, the liquid that came out was a thin, disgusting color, and the bottle itself felt like a carton of milk that had turned to cottage cheese (e.g. there was definitely a solid mass in the center of it, floating inside the thinner liquid).

Someone drunk from the bottle and contaminated it? ;)

> Something acts like the surfactant to keep it from separating.

Gum arabic or Xantham gum?

It does go bad eventually, though, doesn't it? I worry about anything with cream in it that doesn't list an expiration date.

Probably some standard emulsifier is surely added. That for me would be the key bit: Wikipedia suggests "emulsifier containing refined vegetable oil".

Yeah, it's likely made from soybean oil:

> Ingredients: Fresh Dairy Cream, Sugar, Alcohol, Maltodextrin, Milk Products, Cocoa extracts and flavours, Irish Whiskey, Colouring: 150b, Emulsifier: E471, Acidity regulator: E331

https://en.wikipedia.org/wiki/Mono-_and_diglycerides_of_fatt...

Veg oil seems like a bad call for shelf-stability. Sure you can boil off any dissolved O2 and N2 sparge the bottle before sealing it, but that only helps you until you open the bottle.

It does but as pointed out above -- once above a certain % of alcohol as long as it's emulsified the alcohol will kill any bad bacteria.

Veggie oil will go rancid without any help from bacteria.

That being said, Bailey’s isn’t that shelf stable and will likely turn into undrinkable too faster than the average veggie oil will go rancid. And veggie oil can be stabilized to some extent by adding vitamin E.

the agent that prevents its separation is most likely soy lecithin.