Steve writes to the dbd ...
    Scotch is made from traditionally manufactured 2-row malt (no bromates of giberellic acid to speed the process). Takes about 15 days. The malt is similar to a lager malt (less modified than a PA malt) and some or all is smoked above peat fires for flavor. Green malt contains hexanal related chemicals which impart a grassy flavor. Distillers malts are low kilned like lager malt, since they want to preserve beta-amylase. There is no crystal malt used in whisk[e]y making since the Maillard flavors are left behind in the still. Scotch starts with a ~65C mash. That wort is run-off into a fermenter, then more water is added to the spent grist for a second mash around 74C. After that is runoff there is a third mash at around 80C. The three runoffs are combined in a wort around SG=1.050. I think the first mash is thinner than the second and third, but I don't recall the figures. The total mash time is around 8 hours if I recall correctly. The wort is never boiled and the enzymes are still active in the open fermenters. The wort is allowed to undergo some small amount of lactic fermentation before yeast is added - a 12 hour delay before pitching I think. The yeast is conventional brewing yeast from local breweries - random stuff. The fermentation is brief - like 4-5 days before distillation begins. They don't wait for the full completion of fermentation since there is a loss of about 5% of the ethanol to the yeast, which convert it to acetolactate and use it for energy, if they wait. It's distilled in intentionally low efficiency pot stills either 2 or 3 times. The ~5% ABV 'beer' first becomes ~ 15-20% "low wines" then 55-60% barrel strength whisky. The scotch is stored in used oak barrels (bourbon or sherry use) for a number of years - typically a minimum of 10 to 12. It is then diluted with water (various sources) to bottle strength - 43-50%ABV.

    There are several US whiskey making variant, but basically they perform a cereal mash with a large portion of grain - majority is corn typically with some rye (spicy flavored) and wheat (dull flavored). They will then perform a single infusion mash of the result. This thin mash - grist included - is cooled and pitched. US mfgrs are quite picky and secretive about their yeasts. The open fermentation proceeds and the active enzymes continue to produce fermentables during the fermentation. The fermented mash - grist and all - are distilled in a column (coffey, continuous) still. The result cannot be more that 80% pure alcohol in order to retain the name whiskey (US law). The alcohol must be stored in new charred oak barrels at no more than 125 proof for 4 (3?) years before it can be labeled whiskey.

    During distillation the early runnings (foreshots) are removed. This contains a high concentration of acetic acid, esters and any methanol. This only occurs in the first distillation for double or triple distilled pot stills. Late runnings containing fusel alcohols are also removed by stopping the distillation process as the vapor temps rise. When pot distilling Scotch the liquid remaining from the 2nd distillation is added back to the 'green beer' for redistillation.
    Pot stills are basically a pot with a gooseneck lid - alembic stills. Continuous stills are a tall column with several condensation "plates" inside. You can think of the pot still as sort of a broad or crude filter since it doesn't control the vapor temp very accurately. The column still's plates cause a very tight temp control of the vapor at the top. For whatever reason it appears that the pot still does a better job of preserving the flavor components at a given ethanol concentration IMO.

    Properly speaking, sour mash is a US whiskey making term for mash after yeast+lactobacilli have decreased the pH making it acid. US distillers pitch a fraction of sour mash (backset) into the upcoming batch. It adds an active yeast (and lactic) cultures to the new batch and also decreases the pH which makes fermentation easier for the yeast and harder for their competition.

    Jeff adds .."I don't think it contains active yeast and bacteria even though it's often written that it does. Backset is the low pH solid leftovers from the still as I understand it that is added to the mash. A great deal is used in some distilleries, (a quick look at Regan & Regan's "Bourbon Companion" shows 20% (Old Forester) to 41% (Jim Beam)). This was a method that was developed by Jim Crow, a Scottish physician who was an early distiller in Kentucky in the min-19th century and essentially developed modern bourbon."

    HBers sometimes speak of an extended bacterial acidification rest (lactobacilli rest really) as a sour mash, but it's not quite the same thing.

    The book I mentioned "Whisky Flavour:..." by Piggott has a lot of great detail on Scotch mfgr.
Jeff gives me more details on producing a whisky ...
    For a Scotch-style malt whisky, I'd use all malt (duh!), of the palest, lowest protein variety available. I'd mash with water that gives an appropriate pH (just like beer), and aim for a high gravity (1.070 or so, I think). No need to boil as for beer, but the second runnings will dilute. Scotch distilleries do three runnings and use the third running to mash in the next mash. You probably aren't going to have successive mashes.

    For a bourbon I'd use 70 crushed maize, 15% crushed rye and 15% crushed barley malt (highest diastase possible, such as pilsner malt if you can't get distillers malt). Aim for a gravity of 1.070 or so. Add a little malt to the maize and hold at 65C, then raise to a boil for 30-40 minutes, then let cool and/or add cold water to bring to 75C, add rye, hold 30 minutes to gelatinize, then add malt, aiming for 65C. Hold until conversion is complete as indicated by an iodine test. No need to run off the wort - just ferment the entire mash.

    For bourbon's first cousin, rye whiskey, you could use 60% rye, 15% barley malt and 25% maize, or all malted rye (my preference), or other combinations of malted and raw rye.

    To do a sour mash (traditional), first sour some grain by doing a small mash as above, then throwing in some crush barley malt into the cooled mash and hold at warm temperatures for several days. Then add this to main mash with the yeast.

    Cool to 25C and pitch lots of highly attenuating yeast. Dry yeast should work fine. Maybe Danstar Nottingham, perhaps followed by champagne yeast, which is less characterful but more attenuating.

    Keep the temperature between 20-25C if possible.

    Scotch is made from wort that is fermented into beer. With traditional North American whiskeys, the whole mash is fermented and distilled. I would think you'd have to worry about scorching the grains on the bottom of the still.

    Charred oak barrels and warmer year round temperatures contribute to the faster maturation of bourbon (4 - 8 years) as compared to Scotch (10-15 years). Bourbon and rye are greatly influenced by the charred oak barrels. I'd like to make a 100% malted rye and age in uncharred and/or old barrels, much as Anchor Distillery is doing.
Alex H writes :
    you can make very good malt whisky from malt extract and grain mash. I find that it is best to use a blend of two row pale malt extract and pale malt powder. The liquid malt extract has been boiled heavily and adds a nice rich, deep chocolate flavour to your wort and the powdered malt gives it that round fresh malt flavour.

    I use a blend of cracked maize and the above malts in my wort and find that this gives a balance of flavour that is a lot like an Irish Whisky. Due to using malt extracts instead of malted grain I never cook my wort as this would caramelise the malt and give a nasty flavour to the distillate. I used to always use malted grains and cook my wort and go through the whole process but I have found that using malt extract is just as good and so much easier. A lot of emphasis is placed upon SG, enzyme conversion of starches into fermentable sugars and many other esoteric factors but the truth is that these factors are more important in the making of beer or if you are not using added sugar and are relying upon the sugars from the grain starches.

    I use a 120 lt pot still and run to a high wine of 30%, empty the still and then re-distill the high wine to 60%. After distillation, I run the entire run through activated charcoal to remove any impurities. To age my whisky I use a 225 litre American oak barrel that I have heavily charred inside, this is the only way to age whisky as wood chips do not simulate the many chemical reactions that go on inside the barrel over time. You can get smaller barrels but they must be American oak and they must be charred (you can do this yourself.) I use used red wine barrels from Margaret River and rinse them out well with a few litres of white lightning to get the excess red wine out before I char the inside. A famous distillery in Scotland who I will not name has just released a premium scotch whisky aged in used French red wine barrels, selling for over 250 pounds per bottle (my idea first!!) The red wine remnants in the oak give a beautiful, round flavour to the whisky.

    My recipe is as follows;
    10 kg cracked maize
    2 kg liquid malt extract
    2 kg pale malt powder
    22 kg sugar
    1 pouch Alcotec turbo yeast
    Water to make 100 lt (inclusive of above ingredients)

    Fill fermenter with 50 lt hot water.
    Add sugar, malt extract, malt powder and maize. Stir until sugar dissolved.
    Add cool water to fill up to 100 lt mark (will be less than 50 more lt as dry ingredients displace water)
    When mash is approx body temp cast your yeast over the top and stir well.
    Mash will be rich brown colour.
    Seal the fermenter (I never use an airlock. Trust me, you do not need one as the fermentation and escape of co2 is so rapid that nothing will get in)
    Wait approx 10 - 14 days depending on ambient temp.
    Mash is ready when it has gone a lighter colour, has no sweet taste and is non reactive (no foaming response) to added sugar.
    Strain grain out and run through still.
    Age and enjoy!

    Obviously you will have to adjust this recipe to suit your still and fermenter size. This is a great recipe and will produce sublime whisky!!

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