In 1926 they didn't exercise the control and optimization (modification) of malts that is done today. Enzyme concentration and accessibility were lower and more time was needed for them to do their work. I'm surprised that there wasn't a lower temp acid rest (~105F) or a protein rest (~125F) up front but phytase, beta-glucanase, and peptidase all do their things below 140F. Phytase is the most sensitive to heat and is less important (if you properly acidify and buffer) than beta-glucanase which is what breaks down the grain gum and makes your amylases accessible. With today's highly modified malts you can go right to saccharification (starch conversion).
Brewing authentic, ale and lager takes eight hours, and longer, because the triple decoction, and Hochkurz brewing methods are used. Step mashing produces pseudo, ale and lager. Single temperature infusion produces distillers beer, and nothing can be done with the beer to turn it into ale because the brewing method skips three steps that are needed for producing the beers. Only, in homebrewing does high modified, high protein, malt, soaked at a single, high temperature produce ale and lager. The high temperatures denature low temperature activated enzymes that produce ale, Beta in particular. It is chemically and enzymatically impossible to produce ale with single temperature infusion, which makes strike, and target temperature pretty much, useless.
"In 1926 they didn't exercise the control and optimization (modification) of malts that is done today." Nah. Malt became modern in the 19th century when the IOB was founded, and malt spec sheets have been around for about 150 years. Brewers pretty much knew all about malt because they taught the Chemists they hired in the IOB how to test malt. Weihenstephan has been around for about 1000 years, too. Modification and germination are connected, and I'd say, the Great Magnet was involved with that stuff. Abstracts from the IOB are online, and so are malt spec sheets.
"Enzyme concentration and accessibility were lower and more time was needed for them to do their work." Nah. A salesman, selling high modified, malt came up with the statement back in the mid 80s. Also, he said that when modern, high modified, malt was invented, the decoction method became antiquated. To convince people that modern, high modified, malt can be soaked at one temperature to make ale, the salesman, basically, told people who had no idea how ale and lager are produced, that brewmasters were dolts and dullards, that purchased crappy malt, and yet, came up with an exotic brewing method that somehow, magically, turned crappy malt, into brewers grade, malt, and none of that is needed now that modern, high modified, malt, has been invented. Under modified, low protein, malt is brewers grade, malt, and to take advantage of the high quality, malt, the decoction method is used. Under modified, malt is richer in enzyme content, and is more expensive than high modified, malt. Modification (Kolbach, S/T, and SNR) are listed on a malt spec sheet. Malt, 40 Kolbach, and lower, is under modified. Malt should contain less than 10 percent protein. The less protein, the more sugar. Homebrew malt can be 52 Kolbach, and contain 16 percent protein.
"With today's highly modified malts you can go right to saccharification (starch conversion)." From the statement, you need a little more training because you don't know about modification, and you have saccharification, liquefaction, and conversion mixed up. You may not know what occurs during dextrinization, and gelatinization, as well, which involves Alpha, and complex starch, amylopectin.
When Alpha liquefies simple starch, amylose, it happens at a 1-4 link in the starch chain, and saccharification occurs. When amylose is sliced, two chains form, and the name changes. The one chain is the reducing end, and the other chain is the nonreducing end. The reducing end contains 1-4 links, and after Alpha liquefies the links, sweet tasting, nonfermenting types of sugar remain. The nonreducing end is simple sugar, glucose. The purpose of Alpha is to release, glucose, one of three building blocks of life, from starch.
Conversion has nothing to do with starch. Beta is responsible for conversion, which occurs at 60 to 63C. Beta converts the glucose that Alpha releases during liquefaction, into maltose and maltotriose, which are the types of sugar that produces ale and lager. The step is skipped in homebrewing for a few reasons. The first reason has to do with the extra time involved with the conversion rest, another has to do with fermentation because a secondary fermenter is required. Another reason has to do with high modified, malt. For conversion to occur in high modified, malt, an Alpha-Beta enzyme mixture has to be added.
For enzymes, such as, Phytase to work, chemical precipitation has to occur, which doesn't occur when malt is soaked in hot water. Phytase works on potassium and magnesium, pH reduces, and myo-inositol forms. For chemical precipitation to occur at the right time, mash is boiled.
Beta Glucan is mentioned on a malt spec sheet. Don't buy malt high in Beta Glucan, it's that simple, otherwise, an Alpha-Beta Glucanase enzyme mixture has to be added, or a rest at 55C should be used. Beta Glucan is fiber, but it is a bunch of glucose packed together, and enzymes break up the glucose. Depending on the length of the rest, complete saccharification can occur, which isn't a bad thing, because the next temperature rest is for conversion.