I don't fully understand the stepped feeding of wort.
This article is written as though high gravity wort is hard on the yeast. It's not. High alcohol% is. You can pitch any yeast you please and it will ferment until it reaches a point of toxicity. Correct?
On one hand, I kinda get the idea that you are making sure the yeast are consuming some of the longer strain sugars in the first additions, before chomping at the simple sugars in the later additions.
But, on the other hand, they will still find themselves in a high alcohol environment facing a certain percentage complex sugars.
It's trying to treat the beer the same as step feeding simple sugar, but it's not the same at all from a yeast perspective. I'm also not all that convinced that o2 towards the end of the process is of any benefit as I doubt the yeast are trying to propagate much at that point.
Now, if you were oxygenating the new wort and pitching yeast into the new wort and allowing it to ferment to krausen before adding it to the prior fermentation, that would be beneficial as your adding active healthy yeast to the party.
Even if you were to get the yeast in the first ferment to propagate, there could be some costly mutations occurring in such a stressed environment.
Someone please correct me if this thinking is off as yeast health and science is still one of my larger opportunities.
Also, I still think boiling 18g down to 4g is asking for trouble no matter how you shake it.
One would be much better off doing serial mashes(mashing with wort from a previous mash) and decreasing boil time in my opinion. It would require more grain, but in the end I bet you would have a much more fermentable wort. And you could just sparge the other grain and gyle like crazy from it.
I may just have to try my hand at this one day. I have plans for a 60# Barleywine(11g) at some point. Gonna wait to get the RIMS completed before I tackle that one though.
One last word, I still believe fractional freezing is the way to go for BBIIGG beers. It's the way BrewDog does End of History(55% abv) and I believe Tactical Nuclear Penguin(32% abv). The key is being able to push co2 into the fermentor as it freezes(suck back,o2), and also removing the eisbeer afterwards with minimal o2 exposure. Anyone with a 60l Speidel, this is quite easy if you have the ability to add co2(NorCal brewing has some great solutions). When I did an eisbeer in my 60l in an upright freezer, all of the frozen water was a floating ball in the middle of the fermentor and I easily pulled the beer from the stock spigot. I imagine any conical would perform similar. Not so sure about buckets, etc but ice will float regardless so I suppose as long as you have a spigot, anything is possible.
Cheers.