I produce OktoDampf and Oktoberfest. It depends on the weather, whether, I call it steam or lager. I work with nature and sometimes winter is warmer and sometimes it's colder which has a direct bearing on the temperature in the brewery and as long as fermentation and aging temperature are between 40 and 55F, I'm good with it. At 55F it's OktoDampf, at 40F it's Oktoberfest. We're homebrewers, we have carte blanche. Since, nature's inconsistent, malt is inconsistent.
In lager and in light body ale I use 34/70 because it finishes crisp, in Oktoberfest I dump in a bunch of 802 Pils yeast. The reason why I use 802 in Oktoberfest has to do with the way that I brew Oktoberfest. I produce a dextrinous wort similar to Pils just not as high in dextrin as Pils and 802 works well with Pils.
For beer to endure the aging, clearing, and natural carbonation cycle and not thin out, A and B limit dextrin and a type of protein needs to be in wort. A and B limit dextrin are tasteless, nonfermenting, types of sugar responsible for body and mouthfeel. Limit dextrin is stored in amylo-pectin which is heat resistant, complex starch that makes up the tips of grain. Because it is complex starch it's the richest starch in malt. The starch begins to slowly melt at 169F. During the infusion process, mash temperature isn't high enough to allow enough starch to enter into solution before Alpha denatures. The starch is left in the spent mash, it's small, white, particles. The beer lacks body and mouthfeel and it will thin out as it ages.
Mash is boiled a few times during the decoction process which causes amylopectin to rapidly melt. The decoctions are added back into the tun and Alpha liquefies the starch releasing A and B limit dextrin during dextrinization.
When an ale and lager recipe recommends high modified malt, single infusion, only primary fermentation, priming with sugar and using CO2 injection for carbonation, the beer is similar to Prohibition style beer.
To produce OktoDampf (I claim the name!!) and Oktoberfest try Weyermann dark Pils floor malt, the malt is slightly under modified which means it's rich in enzyme content and the malt is low in protein which means there's a bunch of sugar in it. Throw in some sauer malz, won't need specialty malt. Use a Beta rest (140, 145F) conversion happens. Beta converts glucose into maltose and maltotriose which are complex sugars that yeast don't care for. Dump in a few packs of 34/70. After primary fermentation, secondary fermentation where another conversion occurs, yeast gets to love maltose almost as much as it loves glucose. Gravity drops closer to expected FG. Skip diacetyl rest, both styles. After secondary fermentation, into a keg adding no priming sugar or CO2, it won't be needed. During aging yeast works on maltotriose and natural carbonation occurs, the beer clears, flavors smooth out and meld. Gravity falls to expected FG.
To make all of that stuff work some mash needs to be boiled, a protein rest or two thrown in, and patients.
