How To Make Sour Mash

Want to make your own whisky?  Lots of people become distillers as a hobby and in this article we are going to share some info on how you can also get started in this industry.

More and more people are starting to produce their own handmade alcoholic beverages instead of buying these drinks from stores.  It can be hard to shop for the perfect brand of whisky when you haven’t quite sampled all of the different varieties just yet. We all turn to product labels when we don’t quite know a product.  Product labels can offer you a lot of information on the manufacturing and ingredients that alcoholic beverages contain.  

As you scout through the labels of whisky bottles you will come across one common phrase; ‘sour mash’.  For more information on sour mash, refer to the article below;.


What is sour mash whisky?

The phrase ‘sour mash’ on whisky bottles doesn’t mean that the whisky has a sour taste to it.  This term refers to the manufacturing process of this beverage.  

The PH balance of the mash is carefully monitored because high pH levels could result in unwanted bacterial growth.  In every new batch of sour mash whisky, a portion of spent mash from a previous batch is added. By doing this and carefully monitoring the brew, distillers can create new batch of whisky that is similar to the original one.  

What exactly is mash?

The word “mash” simply refers to a mixture of grain, water and yeast that is fermented to produce alcohol.  Mash has is an acidic, nutrient-rich product that is left behind when the distillation process is complete.  

Sour mash whisky manufacturers will use a portion of spent mash in the manufacturing of a fresh batch of whisky.  This spent mash offers acceptable levels of pH and ensures that the same flavour continues into fresh batches. The rest of the spent mash is usually fed to animals. 

What is the difference between bourbon and sour mash?

Bourbon and sour mash whisky is different in their manufacturing methods.  The mash of bourbon whisky is made from corn. Bourbon whisky is double-distilled and aged for a minimum of two years in charred oak barrels.  Sour mash whisky uses the same recipe but uses spent or leftovers from a previous batch to start the process. Many whisky lovers claim that sour mash whisky has a sweeter and deeper flavour than bourbon whisky brands.

What is the difference between sweet and sour mash whisky?

Sour mash is the most common whisky distilling method.  In sweet mash, fresh yeast is used in open-topped vats to get the fermentation process going.  Sweet mash whisky offers a slightly sweeter taste. Many whisky lovers do however prefer sour mash whisky due to a deeper and richer taste. 

What do you need to make sour mash?

To make sour mash you will first need to make a starter mash.  Starter mash can only be made if you have a good fermenter with a proper airlock, such as our 5 Gallon Stainless Steel Still Kit.  For your first batch of sour mash you will also need the following ingredients:

  • 5 gallons of soft filtered water (75 degrees)
  • 7lb cracked corn (6-8 pieces is the proper crack.  
  • 7lb granulated sugar
  • 1 tbsp yeast (distillers yeast if you can find)

You will also need quite a bit of time and patience to complete this process.  

How to make sour mash?

Once you have collected collected all of your ingredients, it is time to start working on your sour mash.  The corn included will produce a bit of alcohol and flavour but the sugar is mostly responsible for producing alcohol.  By adding sugar, the fermentation process will be easier. Making sour mash involves a few fermentation runs. The first run is referred to as the sweet run.  The second run will produce the first batch of sour mash. Sour mash produced after the third or fourth run usually results in better flavour and consistency for your whisky.  

The First Fermentation

This is also referred to as the sweet run and will not produce sour mash just yet.  Here are the steps for the first fermentation process:

Step 1 - Add all ingredients in the order listed above.  

Step 2 - Seal the fermenter lid and leave it.  You will start to see fermentation of sugar within 12 hours.

Step 3 - Leave 3 - 4 days for the ebullition to end.  

Step 4 - The should be siphoned out of the fermenter with a racking cane .  Charge the still Siphoning is the best method because you can pull the wort off the lees without disturbing the lees.  

Step 5 - To start with a 25% basket you will need to collect 1 ¼ gallon of basket.  

Step 6 - Before you start distillation, add 3 ¾ gallons of water to the fermenter so the yeast won’t die.  

Step 7 - Scoop spent corn off the top and replace with equal volumes of new crack corn.  

Step 8 - Pot distillation now needs to be done on the collected basket.  Pot distillation in a reflux still is the easiest method.

The First Run

Pot distillation needs to be performed on the collected basket.  You will need a reflux still to complete this process. Reflux still produces high proof, high quality spirits in a single run.  By law, spirits collected above 80% is not whiskey. These spirits are too light or neutral. The ideal is to create a 70-80% cut.  Here is the process of completing the first run;  

Step 1 - Set your pot  distiller slowly at 2-3 drops of distillate exiting the worm every second.  

Step 2 - Collect 4-5 drops distillate periodically and add an equal amount of water to sip it.  You will learn to identify off tastes.

Step 3 - It might take some time to taste the difference between the heads and tails of your distill but once you do, you will be able to take proper cuts. You can also use a hydrometer to identify the difference between heads, distillate and tails.  

Step 4 - Collect the distilled spirits that average between 70-80%.  Collect 1 ¼ gallon of this basket from this distillation process.  

The Second Fermentation

Your fermenter should still have 3 ¾ gallons of water and old corn from the first fermentation process left.  Here are the steps for this process;

Step 1 - Add 7 pounds of granulated sugar to your collected 1 ¼ gallons of basket from the previous distillation.   The sugar will dissolve easily.

Step 2 - Allow the mixture to cool.  Adding a hot basket to your fermenter will kill your yeast.

Step 3 - Add the cooled sugar and basket mixture to your fermenter.  You should now have 5 gallons of wort in the fermenter. 

Step 4 - Cover the fermenter and allow to ferment 3 - 4 days or until the ebullation ends.  

If all steps were completed correctly, you will now be ready to produce your first run of sour mash. 

The Second Run

Before you can perform your second run, you need to siphon off your wort and charge your still.  Add 3 ¾ gallons of water to your fermenter so your yeast won’t die while you distill.  

Use the same process as the first run.  All spirits under 80% ABV can be considered as Sour Mash Whiskey.   The spirit collected from your still is a palatable moonshine. All of the still can be collected as a sipping whiskey.  

Collect your sour mash

Collect 1 ¼ gallons of basket from the still.  You can now repeat the Second Fermentation process.  Spirits collected from the distillation process hereafter is considered a sour mash whiskey.  And the 1 ¼ gallons of collected basket from every run can be used to create a successful re-run time and time again.

Making your own sour mash is a tiresome yet rewarding endeavor.  It will take a bit of experience to learn to identify the difference between the heads and tails of your whiskey and to perfect your method.  But if all goes well, you should now be able to enjoy your very own batch of sour mash whiskey.