Check out the recipes on Weyermann Malt website. You may find them interesting. Their floor malt is under modified and low in protein, it's available in some HBS's. Being under modified, the malt is rich in enzyme content.
Mashing at 165 denatures Alpha rapidly. Alpha may hang around for 10,15 minutes or so before the heat wipes it out. The highest temperature to use is 162F for no longer than 20, 25 minutes, after that Alpha is pretty much done in. A rest at 162F is not uncommon when a couple of lower temperature rest are used. Mashing temperatures 155F and higher produces a sweet tasting, low alcohol, beer because less glucose is released at high temperatures. For high alcohol beer use 150F. At 150F Alpha produces more glucose than non-fermenting, sweet tasting, sugar. To counteract thinning that occurs in the beer, boil some base malt.
During the brewing process Alpha denatured before saccharification was fully completed. The term is called starch carryover. When you brew use iodine to test for starch, in real dark beer it's tough to use. When the sample is blue/black starch is present, no color change, or colors ranging from yellow-orange, red, deep red to reddish-mahogany, no starch. The different colors mean something. We'll go there after you brew a few batches with all malt.
You have conversion a little bit mixed up which is easy to do because home brew literature mentions starch conversion. Conversion has little to do with starch. The correct term is mash conversion.
Beta amylase is responsible for conversion. The rest temperature is 140 to 145F. Beta stood not a chance at 165F, scratch conversion off. Beta converts glucose released by Alpha during saccharification into complex sugar during conversion, glucose is simple sugar. The sugar that is missing in the beer is maltose and maltotriose, di and tri-saccharides which yeast don't love as much as glucose but during second fermentation and throughout the aging cycle yeast learns to love complex sugar. Another type of conversion occurs during second fermentation. Since, yeast doesn't love complex sugar as much as it loves simple sugar but due to complex sugar being all that is left, yeast comes equipped with an enzyme. During second fermentation yeast absorbs complex sugar through the cell wall, the enzyme converts the sugar back into glucose, the glucose is expelled back through the cell wall and yeast uses it for fuel. Gravity reduces closer to expected FG during second fermentation. During the aging cycle the same thing happens to maltotriose and natural carbonation takes place. Many homebrew recipes skip the Beta rest.
Alpha is responsible for liquefaction, saccharification and dextrinization. Temperature range is 98.6F to denaturing, which is based on temperature and time. Higher temperature, less time. Dextrinization kicks in at 149F and continues up to the point when Alpha denatures but it slowly begins to occur at lower temperatures when complex starch called amylo-pectin is in solution.
Amylo-pectin is heat resistant starch and it slowly begins to "melt" at 169F. Crushing malt into flour will cause issues with starch carry over because it takes heat to rupture the starch. You will notice the starch in spent mash. It is the small, white, particles left over. It is the richest starch in the kernel and the types of sugar within it are A and B limit dextrin. They are tasteless, non-fermenting, types of sugar responsible for body and mouthfeel. The finest Ale and Pils are produced from a dextrinous wort. Brewers producing fine Ale and Pils use the decoction method. When mash is boiled, amylo-pectin rapidly enters into solution and when the decoction is added back into the main mash dextrinization begins when Alpha liquefies the starch at 1-6 links in the chain. During dextrinization, saccharification is also taking place.
When a recipe calls for a single temperature, an hour rest, primary fermentation and sugar priming, the Beta rest was skipped or the guy that wrote the recipe knew something about the quality of the malt. Depending on the level of modification it is very possible that high modified, home brew malt may not contain Beta or the enzyme is so beat to death that it isn't powerful enough to cause conversion to fully occur. To help out a brewer and distiller each sack of malt comes with a spec sheet, believe it or not. Just about everything comes with some type of ingredient list and with malt it's the bunch of chemicals, acronyms and numbers listed on the sheet. The sheet exists because barley/malt are very inconsistent and since malt is inconsistent it is tested. The data from the tests are placed on the sheet. The sheet is used to determine whether the malt is suitable for producing Ale, Lager or better suited for producing grain alcohol. Depending on the modification level of the malt that you are purchasing it is very possible that enzymes will need to be added, that's why enzymes are produced.
A maltster is producing 8% protein, Marris Otter which is great because the lower percentage of protein the more starch, more sugar. Home brew malt is usually 12-16%. The problem with the Marris has to do with the modification which is listed as Kolbach and SNR on the sheet. High modified, home brew malt is usually 42-45 Kolbach. Marris is at the top. Brewers grade malt is under 40 Kolbach and 8 to 10 percent protein. The germination cycle is quite long which causes Alpha to expend a bunch of energy softening starch and releasing sugar during malting/germination. If the malt is used with adjuncts Alpha will not cause full saccharification of the adjunct starch. Enzymes will need to be added to produce Ale and Lager with Marris Otter. Marris otter, Golden Promise and Halcyon were originally intended to make whiskey with.If you are serious about brewing Ale and Lager at the least purchase De Clercks journals, they're about 175 bucks, new. Wulf's pre 1960 journals are about 1000 bucks for the pair.
