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Complete Guide to Mashing and Sparging

For many of us involved in home brewing, stepping up from extract brewing to all grain is the natural progression. While more time consuming, it offers the brewer an unparalleled level of control, typically resulting in higher quality, more exciting beer. But, if processes such as mashing and sparging sound like alien concepts to you, there are a few lessons you’ll need to learn before making the leap!

The mash and the sparge are very important steps in the brewing process, and can allow the brewer to manipulate several variables, such as body, abv and color. It’s also an easy stage to screw your brew up! It’s worth gaining an understanding of what happens while you’re mashing and sparging, and learning step by step how to complete the process successfully.

Relax though, while it may seem complicated at first, it’s actually a fairly easy process. Once you’ve learned a few tips and tricks, you’ll be mashing and sparging with the best of them, and bringing your home brewing up to a new level. So, let’s do this.

Essential lingo

The language of home brewing is rich and varied, and full of words and phrases you’d generally never hear outside of a brewery. Before we look at the process, it’s helpful to take a look at the key vocabulary you’ll need to know when mashing and sparging.

  • Mashing: The mash is the process of steeping crushed malt in hot water, in order to release and break down the starches contained in the malt. By breaking down the chains of complex sugars, smaller, simple sugars are created. The yeast can eventually ‘eat’ these simple sugars and convert them to alcohol.

  • Sparging: The sparge is the process of ‘rinsing’ any remaining sugars from the grain bed, while also diluting the wort.

  • Strike water: The hot water that is mixed with the malt during the mash in.

  • Wort (pronounced wert): The sweet liquid produced at the end of mashing and sparging. It’s basically the beer before it undergoes fermentation.

  • Alpha and Beta amylase: The two enzymes that are responsible for breaking down the larger chains of starch into fermentable simple sugars.

  • Grist: All the dry ingredients that go into the mash tun.

  • Liquor: Basically any water that is used in the brewing process is referred to as liquor.

  • Mash in: The process of mixing the grist and liquor evenly at the start of the mash.

  • Grain bed: The bed of grain and husks that is created in the mash tun during mashing and sparging. Ideally, the husks from the malt will settle near the bottom, creating a natural filter bed.

  • Extract: The amount of fermentable materials derived from the grist. A number of variables can affect this, such as the crush of the malt.

  • Stuck sparge: A brewer’s nightmare! When run off during sparging slows right down it often means the wort is struggling to pass through the grain bed.

The equipment

If you’re moving up from extract to all grain home brewing, you’ll be pleased to hear that you won’t need a lot of additional equipment for mashing and sparging. The following supplies are recommended;

  • Mash tun: A good mash tun will be spacious and well insulated enough to hold a consistent temperature for up to 90 minutes. There are several styles, from plastic, picnic cool boxes, fitted with a filter and tap, to stainless steel tuns. This 10 gallon Infusion Mash Tun from SS brew tech is a great choice and comes complete with various accessories, such as a sparge arm and thermometer. A budget home brewing option is to use a large pot wrapped in a thick towel.

  • Sparge arm: Sprinkling the hot sparge water gently over the grain bed, a sparge arm is a useful piece of kit to have. It will ensure the grain bed isn’t disturbed and distribute the sparge water evenly during sparging. The Ultimate Sparge Arm is a great choice and will fit just about any setup. For a more basic home brewing setup, use an auto siphon with a sprinkler head attachment.

  • Hot liquor tank (HLT): A large vessel capable of heating and holding all the liquor you will require during mashing and sparging. It’s useful to have for home brewing and is essential during the sparge.

  • Mash paddle: An excellent tool for stirring your mash as you mash in. Shaped like an oar, it’s perfect for breaking down any lumps, creating a more consistent mash. This Stainless Steel Mash Paddle is a great addition, and will make short work of a lumpy mash. A normal stirring spoon will also work if you’re on a tight budget.

How to go about mashing and sparging

Okay, so we’ve had a look at the lingo and the equipment, but you’re probably still wondering exactly what you need to do during the mashing and sparging stages. When home brewing, most brewers are happy to stick with a single stage infusion mash, followed by a continuous sparge. The following steps will guide you through these two methods.

Step 1; Prep and cleaning

Start the mash by giving all your home brewing equipment a quick rinse to remove dust and anything else that might have gotten in there. There’s no need to be super sterile clean at this stage, as any undesirables will be killed off during the boil. While cleaning, fill up your HLT with your strike water and heat it up to the desired temperature.

Knowing how much strike water to use, and at what temperature to heat it to depends on your recipe and beer style. Each brew is different, but here are some safe, typical home brewing numbers that you can aim for if you’re unsure;

  • Mash thickness: The ratio depends on your units of measurement.

    • Most brewers in the US prefer a ratio of quarts to pounds, which would be 1.25 parts liquor, to 1 part grist.

    • In metric you’d aim for a ratio of 2.5 parts liquor to 1 part grist, i.e. for each 1 kg of grist, you would add 2.5l of liquor.

  • Mash temperature: The ideal mash temperature is around 150℉. but anywhere between 140 and 158℉.  will also work, though you will see differences;

    • A hotter mash will result in a less fermentable wort with a thicker body - great for low abv beers.

    • A colder mash will result in a more fermentable wort, with a thinner, drier body.

  • Strike water temperature: Grains are typically around 65℉. so to ensure you reach your target mash temperature, you’d be looking at a strike water temperature of around 163 - 164℉..

Of course, these numbers will vary depending on a number of factors, perhaps your malt is hotter or colder, due to storage temperatures. Fortunately, there are a number of online brewing calculators and various home brewing software that you can use to adjust the numbers to suit your needs.

While you’re waiting for the strike water to heat up, crush (if necessary) and weigh out your malt. When milling your malt, you’re looking to keep the husks intact, while cracking the inner. Too fine a grind will produce a flour like consistency, which may be good for extracting sugars, but can also lead to a stuck mash and off flavors.

Step 2; Mashing in

With all of your supplies nicely cleaned up, your strike water at the right temperature and your malts crushed and weighed out, it’s time to mash in. It’s good practice to add strike water up to the mash tun’s filter plate before adding any malt. Next, add the malt and strike water evenly, mixing as you go to avoid clumps, dry areas and hot spots.

Use your mash paddle or spoon to break up any lumps and encourage a consistent temperature. Avoid over stirring as this can disturb the grain bed and cause a stuck mash. Check you’ve hit your target mash temperature at various points in the mash, then, when you’re happy, cover it and leave it for 60 - 90 minutes.

You can give it another brief stir halfway through, and check that the temperature is being maintained. If, when mashing in, the temperature is too high or low, you can add additional hot or cold liquor to the mash to bring the temperature up or down. Keep an eye on how much you add, and take this off the amount of sparge water used.

Step 3; Infusion

While you wait for the conversion to take place, measure out and begin heating your sparge water in the HLT. Again, the amount of sparge water you will require will differ between brews and brewers, but a general rule of thumb would be to heat up around 5 to 6 gallons of sparge water for a 5 gallon batch. Again, online calculators and brewing software can be used for more precise numbers.

Step 4; Conversion check

Once the time is up, it’s time to sparge. But first, it’s worth checking that all the starches have been converted. There is a very simple way to do this in home brewing; the iodine test. Simply remove some spent grain and a bit of the wort, and place on a white plate. Add a drop of iodine, and if it turns clear, you can be sure that full conversion has taken place.

If it hasn’t, and the iodine remains blue, it’s well worth checking the mash temperature, again in various spots around the mash, making sure your thermometer is properly calibrated. If the mash stand was at too low a temperature, the enzymes will not have been active. This can be fixed by heating the mash to the desired temperature. However, if the temperature was too high, the enzymes were probably killed before they could do anything, and unfortunately this cannot be easily fixed.

Step 5; Sparging

Once you’re happy full conversion has taken place, you can start the sparge. Ensure your sparge water is at the right temperature, around 175 - 180℉ should suffice. This will denature the enzymes, improve the flow rate and extract more sugars. If your sparge water is too hot, you will dissolve tannins from the malt, causing off flavors in the finished beer.

  1. Open the tap on your mash tun (or put in your siphon) and draw off the first runnings. You can expect this to be cloudy with some solids in it, that’s normal. Gently return this to the mash, and repeat until the wort runs clear. Be advised that this can take up to 30 minutes.

  2. Now, transfer the run off to the kettle and hook up your sparge arm. Transfer the hot sparge water to the the grain bed, by gently sprinkling it over the top. You don’t want to create holes, instead the sparge water should trickle through the grain bed, rinsing any excess sugars off as it goes.

  3. Be sure that the transfer to the kettle is not flowing too fast. You should be sparging and running off at the same rate to prevent a stuck mash.

  4. Once your kettle is holding the required amount of wort - which will vary from brewer to brewer depending on their equipment - stop the transfer and begin the boil. Typically, a 5 gallon batch will require at least 6 gallons of wort in the kettle. Be sure not to over sparge, as you can start to extract harsh tannins from the malt, leaving an astringent flavor in your finished beer.

Doing the mash

This brief rundown of what is involved in mashing and sparging really is just the tip of the iceberg, but it’s enough to get you started on all grain home brewing. There are many factors you can eventually learn to play with, such as mash thickness and temperature to improve the body of your beer among other things.

For starters, it’s well worth developing an understanding of the process. Every brewery is different, and you’ll find it will take a few brews to get used to your equipment. Working out what your losses are, and where they are occurring is an important step forward when crafting your own recipes. This knowledge will also ensure you measure out the right amount of strike and sparge water every time.

Once you’ve done it a few times, you’ll wonder why you were ever wary of mashing and sparging. And, when you taste how good your all grain brews are, you’ll be rushing to do it all again! Home brewing is a seemingly endless learning curve, so sit back, take your time and enjoy a good beer. Then, do the mash…

...The brewers’ mash.