Malt whiskey is the whiskey style that scotch whiskey falls into. Basically, scotch is an all-grain malt whiskey made entirely of 2-row barley malt and water. Scotch whiskey is simply malt whiskey that is made in Scotland. Scotch whiskey generally has other elements contributing to its flavor, such as the smoky, peaty flavor that comes from barley malt that was kilned over a peat fire and water from a natural source that contains peat and heather characteristics that are imparted from the ground it flows from. However, Lowland scotches have very little of these characteristics, as do malt whiskies from parts of the world other than Scotland, and these malt whiskies are excellent in their own right.
Some scientists claim that the water used in on distilling has little to no effect on the taste. In my opinion these people have no idea what they are talking about. Most distillers and hobbyists alike agree that water does make a difference in flavor. Most of the liquor that is sold in stores is 40% alcohol. This means that 60% of the liquid is water. Choosing what water to use is especially important when you are cutting your spirits down to a more palatable percentage. I would recommend using bottled water when it comes to cutting your spirits. Some tap water can cause your whiskey to become cloudy. This however will not affect the taste of your whiskey. You may want to first test the water on a small glass before adding it to your entire batch.
Unlike corn or rye mash, malt mash is not fermented with the grain still in the mash. The grain in a malt mash is strained out and rinsed before fermentation, much the same way that beer is made.
Malt mash is made just lie an all-grain beer except there are no hops and no kettle boil. However, since there’s no kettle boil, sparging, a process usually employed when making beer (this is done by straining and rinsing the grain in hot water), runs the risk of over diluting the mash, so rinsing the grain must be handled carefully. One precaution would be to limit the over all amount of mash water that’s used in the entire mash cycle.
The following is a single infusion-mash method for making an all grain malt mash.
One consideration when it comes to making a malt whiskey mash is that a whiskey mash typically has an originating SG between 1.06 and 1.07. This is a little difficult to achieve with straight infusion mash with no kettle boil, so this recipe is formulated to yield a SG of 1.06 or a little higher, based of a modest mash extract efficiency of about 72%.
Mash extract efficiency is a measure of how well the brewing operation extracts the carbohydrates from the grain and renders them to the finished substrate for fermentation. Ideally, a brewing operation would extract 100% of the carbohydrates from the grain, but various inefficiencies in the process, such as rinsing the grain, result in some of them remaining in the spent grain.
Home operations tend to not be as efficient as commercial operations, so the modest mash-extract efficiency assumed for this recipe is 72%.
All grain whiskey ingredients:
25L tap water
2 tsp Gypsum
1 litter of backset if you have it. (backset it the liquid that is left in the still after your beer striping run)
14.5 lbs of crushed 2-row barley malt
1 package of whiskey yeast
Steps for making all grain whiskey mash:
Prepare 25L of mash water by thoroughly mixing 2-tsp of gypsum into the water and adjusting the pH to about 6.0 with acid or backset.
Place 17L of the mash water in a large pot on the stove, and turn the stove on high. Cover the pot, and let the water heat up to the conversion strike temperature of 160 F. Periodically, you will have to stir the water thoroughly and check the temperature as the water heats up until the strike temperature is reached.
When the water is at the strike temperature, turn off the heat, and stir in the 14.5 pounds of barley malt. The temperature should come to rest at about 150 F or higher. Stir the mash for about 5 minutes.
Cover the mash pot and leave it for 90 minutes for the starches to convert to sugar. It’s helpful to stir the mash every 15 minutes or so during this conversion rest. The temperature will start out around 150 F and will drop to about 140 F throughout the 90 minutes. This is just about right sing the ideal conversion temperature is about 145 F, which is about midway between starting and ending temperatures.
Toward the end of the conversion rest, place 4L of mash water in the smaller pot and heat it almost to boil. This will be used shortly after the conversion rest is complete.
Next the mash must be strained into a fermenter using a strainer of a straining bag. After this, return all the grain from the strainer of straining bag to the mash pot, and add the 4L of hot water from the smaller pot. Mix the grains thoroughly in the hot water, and strain it again into the fermenter. Return the grain to the mash pot again and repeat this rinsing process once more with another 4L of near boiling mash water.
Once the grain has been strained and rinsed into the fermenter, the mash should be chilled to yeast-pitching temperature which is around 75 degrees F.
You will want to avoid using more than 25L and water. The more water you use, the lower the SG will be. You do not want your SG to be below 1.060.
From this point on the mash can be fermented and distilled in the usual manner. Since the mash has already been strained it won’t require straining after fermentation, but it must be carefully siphoned off its yeast sediment before being transferred to the still.