Brewing Water Part 4
HARDNESS vs ALKALINITY

Today we’re taking the next step:
Hardness versus alkalinity,
why brewers mix them up,
and how Residual Alkalinity, or RA, predicts mash pH.

This is Part 4 of the brewing water series.
Links to the earlier videos are in the description.

Let’s get into it.

HARDNESS VS ALKALINITY

Hardness and alkalinity get mixed up constantly
because both are reported as CaCO₃.

But they are completely different things.

Hardness comes only from calcium and magnesium.
Doesn’t matter what salts they come from,
if the ions are calcium or magnesium, they count as hardness.

Alkalinity comes almost entirely from bicarbonate.

Two different roles.
Two different behaviours.
Same units purely for convenience.

HARDNESS IN BREWING

Hardness affects mash performance.

Calcium improves enzyme stability, conversion, hot break,
yeast flocculation, and clarity.

Magnesium provides a small nutrient boost for yeast.

Hardness generally helps lower mash pH.
It does not raise it.

WHY CaCO₃ IS USED FOR BOTH

Labs express both hardness and alkalinity “as CaCO₃”
because calcium carbonate makes the maths easy.

Its molecular weight is 100.
Its equivalent weight is 50.
And it reacts cleanly with acids.

It’s simply a unit of convenience.
The chemistry is completely different.

RESIDUAL ALKALINITY, THE MISSING LINK

Here is where hardness and alkalinity finally come together.

Residual Alkalinity, or RA, tells you:

After calcium and magnesium have lowered mash pH,
how much alkalinity is still pushing the pH back up?

High RA means your water tends to raise mash pH.
Low or negative RA means your water lets pH fall easily.

Two waters with the same alkalinity
can behave very differently in the mash
depending on the hardness levels.

RA is the tug of war
between hardness pulling down
and alkalinity pushing up.

It doesn’t give an exact mash pH,
but it tells you which direction your water wants to go.

Understanding RA helps you predict mash pH far better
than alkalinity alone.

BREWER’S QUICK GUIDE

Hardness high and alkalinity low,
great for pale beers.

Hardness low and alkalinity high,
pale beers will fight you, you will need acid or RO dilution.

Both high, as long as you keep them reasonable,
are great for dark beers.

Both low,
like RO water,
build any profile you want.

HOW TO BALANCE HARDNESS AND ALKALINITY

To raise hardness:

Add calcium chloride, calcium sulfate, or magnesium sulfate.
Different salts change flavour balance differently.

To lower hardness:

Use RO dilution.

To balance hardness with alkalinity:

Adjust both separately,
then look at RA to fine-tune mash behaviour.

Brewing software makes this much easier,

but understanding the concepts gives you control.

Brewing Water Part 3
Alkalinity

Today we’re diving into a topic that confuses brewers more than almost anything in water chemistry: alkalinity.

pH VS ALKALINITY

pH and alkalinity are not the same thing. pH is the ratio of acid to alkaline.

Alkalinity is the amount of alkaline that is present. Two completely different things.

Let me make this clearer with a couple of analogies.

CAR AND CARAVAN ANALOGY

Imagine you are towing a caravan.

The car pulling it is acid. The caravan is alkalinity.

If the caravan is light, even a small car can move it.

That is low alkalinity, and a tiny bit of acid shifts the pH easily.

If the caravan is heavy, the car struggles.

That is high alkalinity, and the pH barely moves even with a fair bit of acid.

That is alkalinity, resistance to lowering pH.

MARBLES ANALOGY

Now imagine marbles.

Red marbles are acid. Blue marbles are alkaline.

One red and one blue marble gives you a neutral balance,

I am using pH 7 here simply as a teaching analogy.

But the alkalinity is tiny, add one more red, and the pH shifts dramatically.

Ten red and ten blue, still neutral, but alkalinity is higher,

add one red and the pH only moves a little.

One hundred red and one hundred blue, still neutral, but alkalinity is huge,

add one red marble and the pH barely moves.

pH is the balance. Alkalinity is the amount.

THE THREE DEFINITIONS OF ALKALINITY

Water treatment people use three definitions.

Number one, Alkalinity is the water’s ability to resist a pH change.

Number two, Alkalinity is the water’s ability to neutralise acid,

in other words, how many bases in the water can mop up hydrogen ions.

In brewing, that is almost all bicarbonate.

Number three, Alkalinity is how much acid it takes to push the water down to pH 4.5.

Below that, alkalinity is gone, and pH falls very quickly.

Your water report’s alkalinity number is based on this pH 4.5 test.

pH 4.5 is the standard endpoint for total alkalinity titration.

We will go deeper into that another time.

WHAT ALKALINITY ACTUALLY MEANS FOR BREWERS

Alkalinity is your water’s ability to resist a drop in pH.

It comes from bicarbonate, carbonate, and a tiny bit of dissolved CO₂.

Here is an important detail, in normal drinking water, pH 7 to 9,

over ninety eight percent of the carbonate system is bicarbonate.

So for brewers, alkalinity basically is bicarbonate.

Bicarbonate is the primary buffering system in brewing water.

WHY ALKALINITY MATTERS

High alkalinity raises mash pH, it can make pale beers harsh, dull, or grainy.

Low alkalinity lets mash pH fall easily, great for pale beers,

but it can fall too low in dark beers.

Very low alkalinity, around 0 to 30 ppm, can make beer taste thin or watery.

Moderate to high alkalinity, around 100 to 200 ppm,

helps buffer the acidity of roasted malts in stouts and porters,

and it prevents acrid, burnt flavours.

Pale beers want low alkalinity.

Dark beers want moderate to high alkalinity.

HOW TO ADJUST ALKALINITY

To lower alkalinity

Use lactic acid or phosphoric acid, acidulated malt,

or dilute with RO or distilled water.

Prefer lactic or phosphoric,

they are predictable, repeatable, and easy to calculate.

Why not rely heavily on acidulated malt?

Because its acidity varies between maltsters,

large amounts can add lactic flavour,

and it makes mash pH correction slow and imprecise.

Dilution

Dilution works well when you do not need a huge correction.

If your alkalinity is 100 ppm and you want around 50,

a simple one to one mix of tap water and RO or distilled water

will get you close.

De- alkalisation by boiling

You can also remove alkalinity by boiling. Bring the water to a rolling boil.

You may add a small sprinkle of chalk to speed things up,

but boiling alone will remove some alkalinity.

Boiling drives off CO₂, and once the CO₂ is gone,

the water cannot hold as much bicarbonate.

Calcium and bicarbonate will crash out as chalky solids.

Let it cool, let it settle, and pour off the clear water from the top.

Done properly, this usually leaves you with around 60 to 90 ppm alkalinity.

To raise alkalinity

Use baking soda, it is the easiest and most predictable method.

You can use chalk, but it barely dissolves unless the water is carbonated,

so it is difficult to use correctly.

Slaked lime works too, but it is tricky, it's easy to over correct and can be corrosive.

Most brewers should stick to baking soda.

So in summary:

pH is the balance.

Alkalinity is resistance to lowering that balance.

And bicarbonate is the superstar behind it all.

In the next video, we will look at how alkalinity interacts with hardness,

and how Residual Alkalinity, or RA, predicts mash pH even better.

Brewing Water Part 2
pH

Every brewer seems to know that one guy who says,

“Mate, you ONLY need this magic number,” or

“This ONE mineral is all that matters.”

Yeah… nah, not even close.

That’s marketing hype mixed with wishful thinking.

Water chemistry is a team sport, not a solo act, and pH

is one of the Most Valuable Players.

From your mash, to the boil, into the fermenter, and all

the way to that final pint, pH is quietly influencing

everything, like a backstage manager that never sleeps.

And sure, you might fluke a good beer without paying

attention to it, but if you want to dial things in, fix

problems, and make beer that tastes intentionally good

instead of accidentally good, pH is your new best mate.

This is Part 2 of my brewing water series, so if you

missed Part 1, it’s worth watching. It’ll make some of the

terms in this video make a lot more sense. And, like

always, I tuck a bit of bonus science at the end for the

curious minds who enjoy a nerdy nightcap. If you

skipped that in Part 1, or haven’t watched it at all, there’s

a link in the description.

Fun Fact - Oxygen means Acid Maker

Alright, before we start throwing numbers around like

we’re filing tax returns, it helps to understand why pH

does what it does and what’s actually going on behind

the scenes.

So let’s kick off with the basics.

What does pH mean?

pH p=Power H=Hydrogen

pH stands for the “Potential of Hydrogen”

More accurately, the "p" is a mathematical notation that

stands for the negative logarithm (base 10) of the

concentration or activity of hydrogen ions ([H⁺]) in a

solution. Remember at School, yep one of those buttons

on your calculator Log Sin Cos.

You might be used to hearing “acid and alkaline” but

since we’ll be talking about alkalinity in another video,

it’s less confusing to use the word "base" or “basic”. So

you have acids and bases.

In simple terms, pH is a scale that tells us how acidic or

basic water is. It’s based on the concentration of

hydrogen ions present, acids gain hydrogen ions and

create hydronium and bases are created by losing

hydrogen ions and creating hydroxide but because

those numbers get incredibly small, we use a logarithmic

scale to make it easier to work with.

A logarithmic scale simply means each 1 step change in

pH represents a tenfold change in acidity. For example,

something with a pH of 5 is ten times more acidic than

something with a pH of 6.

If we look at the pH range from 0 to 14, each step is a

tenfold change, which means the entire range spans a

factor of 100 trillion. That’s an almost unimaginable

difference. If pH 0 were represented by a single 1mm

grain of sand, then pH 14 would be 100 trillion grains,

enough to fill 40 Olympic swimming pools or build a

small beach. If pH 0 was 1 second, then pH 14 would be

over 3 million years. This is why the pH scale uses

logarithms, to compress a truly enormous range into a

simple number.

Why does pH matter in brewing

pH is crucial because it affects almost every stage of brewing:

1. Mash Efficiency

Enzymes like amylase convert starches to sugars

best in a slightly acidic range, around 5.2 to 5.6.

Outside this range, enzyme activity drops, reducing

sugar extraction, efficiency and ultimately affecting

alcohol content.

2. Flavour Development

pH affects the taste of the final beer:

Lower pH can make beer taste sharp or tart.

Higher pH can lead to dull or soapy flavors.

pH also influences hop utilization, too high or too

low can reduce bitterness extraction.

We will dive deep into pH and beer flavours in a

future video.

3. Yeast Health & Fermentation

Yeast prefers a slightly acidic environment. Correct

pH helps yeast ferment efficiently and reduces the

risk of off-flavors or stalled fermentation.

4. Microbial Stability

A lower pH helps inhibit unwanted bacteria,

improving the beer’s shelf life and safety.

5. Clarity & Stability

pH affects protein precipitation and polyphenol

interactions, which influence clarity and haze formation.

How to Measure pH

1. pH Test Paper or Indicator Sticks

These strips change colour depending on the

acidity or alkalinity of your solution. You dip the strip

into your liquid and compare it to a colour chart.

Each colour corresponds to a different pH. Though I

am yet to find any with high accuracy. And with dark

beers that can change the colour of the strip,

accuracy is near impossible.

2. pH Meters

A probe is dipped into the wort or beer, giving a

precise digital reading. Many, if not all serious

brewers who care about their beer use pH meters.

They are used through the whole process from

mash to fermenter. A detailed test equipment video

will be later in this series. A quick tip for those

already using them, calibrate whenever you use

them and make sure the calibration fluid is at room

temperature around 20c or 68F and the same with

the wort sample, doesn't matter if it has ATC

Automatic temperature correction or not, to get

accurate readings it’s what you have to do.

Tip

To some people this might sound odd, but in brewing, as

long as you’re starting with potable water, water that’s

safe to drink, the actual pH of your tap water isn’t a big

deal, it doesn’t matter. In most places it falls somewhere

between 6.5 and 8.5 anyway. Once you add grain, the

mash naturally contains buffers that pull the pH into a

range that's easily tweakable when needed, so the

starting water pH rarely affects anything by itself.

Buffers, that brings us to Alkalinty, that's for the next

video and it is hugely important.

pH tells us the ratio of acid to base, but it doesn’t tell us

how much total acid or base is in the water. That’s

where alkalinity comes in.

In the next video I’ll show exactly why alkalinity matters,

and why water with high alkalinity is much harder to shift

in pH than water with low alkalinity.

Brewing Water Part 1

Water Chemistry 101

Beer is about 95% water. But here's the crazy part. Most brewers know way more about their hops and grains than their water. And that's a mistake. Because water chemistry isn't just science. It's flavor chemistry. Get it right and your beer sings. Get it wrong and your beer's going to taste like ****.

The minerals in your brewing water can make all the difference between a crisp Pilsner, a malty stout, and a punchy West Coast IPA. This is one of those topics that can feel overwhelming, but stick with me through this series. I'll keep it short, simple, and practical so you can brew your best beer.

What is brewing liquor? When brewers say brewing liquor, we don't mean the booze, the finished beer. We're just talking about our water prepared with the right minerals for brewing.

Tap water varies wildly depending on where you live. Some areas have soft water with very few minerals. Others have hard water packed with minerals like calcium and bicarbonates. By treating our water, we can adjust mash pH into the ideal range. We can enhance malt or hop character, improve yeast health and stability, and really importantly, we can completely change the mouth feel and flavor of a beer.

Now, if you Google brewing water chemistry, it's easy to be overwhelmed with different advice, a jungle of equations, and scary looking spreadsheets. But don't worry, I'm going to walk you through this step by step. By the end, you'll have a process you can use for life. Whether you're brewing in your garage or at a full scale brewery.

Before you change anything, you need to ask yourself why. Why are you doing it? What are you trying to achieve? Because a hazy pale needs a very different water profile to something like a crisp pilsner. Too many brewers just throw in salts and hope for the best. Even when using brewing software or AI tools, even if you don't understand what you're looking at, the answers it's giving you, you're still just guessing and hoping it's right.

So, pick the style you're going to brew, and know your target. Here's a big mistake I see people make all the time. People try to copy regional water profiles, like the famous Burton-on-Trent water, often used for English ales. Sounds authentic, right? But here's the truth. Even centuries ago, those brewers were changing their water. They didn't love what came out of the ground, and they changed their water to make a better beer. So, take inspiration from history, but don't chase their water, chase their flavor. Design your water for the beer style, not the postcode.

Know your starting water. You need to know what you're starting with. What's in your water at home? One way is to pay for a test. You send a sample off to be analyzed and they send you a detailed report back, but quite expensive. It's at least a couple of hundred the last time I looked. Another way is to obtain a water report from your local water authority. They're also self-test kits, but they can be a little inaccurate and again sometimes expensive.

And then there's RO water. RO water is reverse osmosis water. It's highly filtered water and there is next to nothing left in it. There's still a little bit of stuff but not much. The trouble with all these methods though is water can vary from week to week and season to season. For instance, where I live, they can access at least three different dams for my water supply. And while the water authorities monitor and treat it all, it's not always the same. And of course, that just changed that expensive water analysis you paid for.

Even when it comes to RO water, the age or quality of the filters changes over time. If you own a commercial working brewery, you might be able to afford to test and change your filters all the time, but as home brewers, that's just another cost. Keeping diaries of usage by time and liters or gallons can help with knowing when to change them.

What I suggest at the start, if you don't filter, is to use the water authority report averages. It's the closest numbers you're going to get. But still, things like old piping in your neighborhood can throw those numbers out, too. You can get cheap TDS meters. They test for total dissolved solids in your water, and then you can regularly check your water and maybe pick up any unexpected changes. TDS meters can't give you the full details, but it will let you know if something is wrong. We'll discuss test equipment further in another video.

So, starting with your water authority's average numbers gives you the best baseline. If that info isn't online, send them an email. Be clear about what you need. I'll drop a link to a list of what you should ask for in the description. If you don't get the answers you want straight up, ring them, ask them who you need to speak to that will know.

You may have a local brewery, or a homebrew shop, or even a homebrew club that might be able to help you with the numbers. And here's a bonus tip. If you have to, go and ask your local aquarium store or garden center. The good ones know their water profiles inside and out.

So, to wrap this section up: know what you're trying to achieve and know your starting water. That's your foundation.

Before we finish, here's a quick bit of science that will make the next videos a little bit easier to understand. I think most people will know that water is H₂O and its polarity makes it one of nature's best solvents. That just means it's really good at dissolving things. It's why water can pull sugars, proteins, and flavors out of your malt and hops. It's also how it carries the minerals we add to shape our beer's taste and texture.

As a chemical compound, a water molecule contains one oxygen atom and two hydrogen atoms connected by covalent bonds. In chemistry, polar means that a molecule has an uneven distribution of electric charge. One end is slightly positive, the other slightly negative. In water, the oxygen atom carries a partial negative charge and the two hydrogen atoms carry partial positive charges.

So when we add something like calcium chloride, written as CaCl₂, and give it a good mix, the salt dissociates. It breaks apart. Its ionic bonds break and it splits into three ions: one calcium ion, which is positive, and two chloride ions, which are negative. Opposites attract, the water helps them to break apart. And that's why, in a very simplified way, water is so good at dissolving salts.

And that'll help you understand some future videos. That's the chemistry behind the flavor.

Thanks for reading. Grab your pH meter because next time we're getting into the good stuff.

Cheers, and I'll see you then. Keep on brewing.

The famous Charlie Talley Star San interview

On my old Cellar Dweller website one of the most popular posts was the Charlie Talley from Five Star Chemicals interview, they made Star San. He gave Basic Brewing Radio his story and Star Sans story, it's a long video so I've made a condensed version of the information. Thanks to Basic Brewing Radio. Cheers!

BLEACH, STAR SAN, AND THE TRUTH ABOUT SANITIZING YOUR HOMEBREW
An Interview with Charlie Talley of Five Star Chemicals

Sanitation can make or break your homebrew. In this interview, Charlie Talley, founder of Five Star Chemicals and inventor of Star San, shares decades of experience, explains how bleach really works, and clears up common myths about sanitizers in brewing.

WHO IS CHARLIE TALLEY?
Charlie has been in the chemical specialty industry since 1968 and worked as a chemist for Penwalt Chemical, a major manufacturer of bleach and chlor-alkali products. He developed the formula that would become Star San in 1971 and introduced it to homebrewers in the early 1990s. He has deep experience with both bleach and modern sanitizers.

BLEACH AS A BREWING SANITIZER
Bleach (sodium hypochlorite) is one of the oldest sanitizers available. The EPA even bases many germ-killing tests on chlorine. Many homebrewers avoid bleach because of bad experiences, but Charlie emphasizes that bleach can be very effective if it is used correctly, especially when it comes to pH.

WHY pH MATTERS WITH BLEACH
Household bleach is usually too alkaline (too high in pH) to kill effectively. Manufacturers add sodium hydroxide to stabilize bleach on the shelf, but that high pH prevents the formation of hypochlorous acid, the compound that does the actual killing. Lowering the pH makes bleach far more effective.

IMPORTANT SAFETY WARNING: BLEACH + VINEGAR
Never mix concentrated bleach and vinegar directly.
For brewing use, both are added separately into plenty of water. Mixing them directly in concentrated form can produce dangerous chlorine gas. If you are unsure, use a no-rinse sanitizer instead.

WORKING BLEACH RECIPE FOR BREWING EQUIPMENT
(Using typical 5% household bleach)

1 ounce bleach in 5 gallons of water = about 80 ppm chlorine
Add 1 ounce white vinegar to the diluted solution

This concentration provides effective sanitation.

Contact time: about 30 seconds
Rinsing: not required at this strength (optional)

If you choose to rinse, remember that tap water may introduce microorganisms, which is why many brewers prefer no-rinse sanitizers.

CLEANING VS. SANITIZING
Charlie stresses that “sanitation is 90% cleaning.”
If your equipment is not completely clean, sanitizer cannot reliably save it. Scrubbing, removing film, and paying attention to detail are far more important than which sanitizer you choose.

Sanitize right before use. Do not sanitize equipment and then leave it sitting for days or weeks. Clean first, store clean, and sanitize immediately before brewing or packaging.

OVEN STERILIZING BOTTLES
Dry heat sterilization does work if done correctly.

Place bottles in a cold oven
Heat to 350°F (177°C) and hold for 3.5 hours
Turn off the oven and let everything cool inside

This gives effective sterilization. Bottles stay reliably sterile for about one month if kept covered with foil.

WHY STAR SAN WAS CREATED
Star San was developed as a response to iodophor sanitizers used on dairy farms. Charlie wanted a sanitizer that:

• Works in the presence of organic material
• Has broad killing power
• Provides some cleaning action
• Is safe and easy to use

Star San is an acid anionic detergent sanitizer. The acid alone does not kill well. The surfactant alone does not kill well. Together, in the right ratio, they are extremely effective against bacteria, yeast, mold, and even spores.

DON’T FEAR THE FOAM
Many homebrewers are concerned about Star San foam. Charlie designed Star San using ingredients that are food-grade or Generally Recognized As Safe. At working dilution (1 ounce per gallon of water), the foam is harmless.

Residual foam does not harm yeast. In fact, when Star San becomes more diluted and its pH rises, the residues can act as nutrients and help start fermentation more strongly. This is the origin of the famous advice: “Don’t fear the foam.”

REUSING STAR SAN SOLUTION
EPA rules require sanitizing solutions to be made fresh each time. However, in practical brewing use:

A Star San solution made with distilled or deionized water can remain active for months.
A solution made with hard water will turn cloudy over time as minerals react with Star San.

Signs a Star San solution is still good:
• pH around 3.0
• The solution remains clear

Once it becomes cloudy, it is time to replace it.

If your sanitizer gets visibly dirty with debris or trub, that usually means your cleaning step needs improvement.

KEY TAKEAWAYS FROM CHARLIE TALLEY

• Cleaning is the real foundation—sanitizing is insurance.
• Bleach can be a very effective brewing sanitizer if used safely and correctly.
• Never mix concentrated bleach and vinegar directly.
• Cheap, unscented bleach is usually better for brewing sanitation.
• Use bleach at 1 ounce per 5 gallons, plus 1 ounce of vinegar added separately into the water.
• Sanitize immediately before use.
• Star San is highly effective, widely safe, and yeast-friendly.
• Don’t fear the foam.
• Star San mixed with distilled water can last months if kept clear and around pH 3.

Used properly, both bleach and Star San can help produce consistently clean, infection-free beer. The real secret is understanding how they work, and cleaning thoroughly.