how true are some claims that people make of taking yeast into the realms of 15%

Ingredients
1

I’ve seen some claims that it is doable, though difficult to take some ale yeasts working on wort (not mead/wine/etc) up to 18% or even higher, can anyone confirm this and give advice?

-2 or 3 steps up total
-obviously extra yeast nutrients including staggered nutrients
-lots of oxygen and a second oxygenation at 24 hours since activity?
-good amount of simple sugar obviously

particular strains? i got excited by seeing wlp099s stats, but people seem to be generally pretty negative about it, extreme esters, much lower actual alcohol results for most people.

2

Before I knew what I was doing I easily got the chico strain to 12% and am sure I could have got 2-3 more.

3

Plenty of oxygen early, big pitch, staggered additions. Sure but is it going to make a beer you want to drink?

4

Club members have done it up to 18%. And those were surprisingly good. Lots of attention and giving the yeast what they need.

5

My biggest beer went from 1.142 to 1.024, so about 17% IIRC. I used WLP037 (Yorkshire Square), and stepped it up twice. Beer 1 was a 1.040 brown ale. I used about a third of the slurry from that to brew a 1.060 Old ale, then I pitched my 1.142 barleywine on the whole yeast cake. I oxygenated with O2, then hit it with a second dose of O2 about 18 hours later. I did an open ferment in a bucket, but that was primarily because of the yeast strain I was using.

One thing I would strongly recommend is to produce a wort that is highly fermentable. Mash long and low, and consider using simple sugars in the wort.