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Good day. I'm Gavin.
Welcome back to the Home Brew Network. Today we're talking about pH.
The tiny little number that somehow has a massive impact on your beer. It's small, it's sneaky, and if you ignore it, it will absolutely turn your flavor into a crime scene.
I've
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been brewing for over 35 years, trained in brewing science and commercial brewing, and the whole point of this channel is to make this stuff simple. No chemistry degrees needed, no spreadsheets that look like they just came from NASA.
Just clear info so you can make your best beer.
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Now, 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." 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
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players from your mash to the boil to the fermenttor and all the way to the 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
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things in, fix problems, and make beer that tastes intentionally good instead of accidentally good, PH is your new best mate. This is part two of my brewing water
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series. So, if you missed part one, 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 in at the end for those curious minds who like a nerdy night cap.
If you skipped part one or haven't watched it at all, there's a link in the
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description. Fun fact, oxygen means acid maker.
All right, 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
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kick off with the basics. What does PH mean?
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
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or activity of hydrogen ions in a solution. Remember at school one of those buttons on your calculator, log in tan co.
Yeah, that you might be used to hearing acid and alkaline, but since we're talking about alkalinity in another video, it's less confusing to
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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 a solution is. It's based on the concentration of hydrogen ions present.
Acids gain hydrogen ions and create
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hydrronium. 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 one
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step change in pH represents a 10-fold change in acidity. For example, something with a pH of five is 10 times more acidic than something with a pH of six.
If we look at the pH range from 0 to 14, each step is a 10-fold change,
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which means the entire range spans a factor of 100 trillion. That's an almost unimaginable difference.
If pH0 were represented by a single 1 mm grain of sand, then pH14 would be 100 trillion grains, enough to fill 40 Olympic
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swimming pools or build a small beach. If pH was 1 second, then pH14 would be over 3 million years.
This is why the pH scale uses logarithms to compress a truly enormous range into a simple number.
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We're going to have a quick look at the pH scale. A couple of examples there from gastric acid right down the acid end up to costic right up the basic end.
And of course an outline from where the brewing liquor starts and then where we
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mash at and where the beer ends up. We'll go deeper into this a little bit later in the series and give you some real world examples.
Why does pH matter in brewing? PH is crucial because it affects almost every stage of brewing.
The mash mash
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efficiency. Enzymes like amalayise convert starches into sugars best in a slightly acidic range around that 5.2 to 5.6.
Outside this range, enzyme activity drops, reducing sugar extraction and ultimately
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affecting your alcohol content. Flavor development.
PH affects the taste of the final beer. Lower pH can make a beer taste sharp or tart.
Higher pH can lead to dull or even soapy flavors. pH also
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influences hop utilization. Too low or too high can reduce bitterness extraction.
We will dive deep into a pH and beer flavors in a future video. Yeast health and fermentation.
Yeast prefers a slightly acidic environment as well. Correct pH helps
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yeast ferment efficiently and reduces the risk of off flavors or stalled fermentss. Microbial stability.
A lower pH helps inhibit unwanted bacteria, improving the beer shelf life and safety. Clarity and stability.
PH affects protein precipitation and
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polyphenol interactions which influence clarity and haze formation. How to measure pH?
PH test paper or indicator sticks. These strips change color depending on the acidity or alkalinity of your solution.
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You dip the strip into your liquid and compare it to a color chart. Each color corresponds to a different pH, though I'm yet to find any with high accuracy.
And with dark beers that can change the color of the strip, accuracy is near impossible. PH meters.
A probe is dipped
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into the W or beer, giving a precise digital reading. Many, if not all, serious brewers who care about their beer use pH meters.
They used throughout the whole process from mash to fermenttor. A detailed test equipment video will be later in this series.
A
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quick tip for those already using them. Make sure you calibrate them whenever you use them.
Make sure your calibration fluid is at room temperature around 20° or 68° Fahrenheit. And the same with your work sample.
It doesn't matter if it has ATC written on it, automatic
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temperature correction or not. to get accurate readings is what you have to do.
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
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doesn't matter. In most places, it falls somewhere between 6.5 and 8.5 anyway.
And once you add the grain, the mash naturally contains buffers that pull the pH into a range that's easily tweakable when needed.
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So, the starting water pH rarely affects anything by itself. Buffers.
That brings us to alkalinity, and that's for the next video, and it's 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
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water. That's where alkalinity comes in.
In the next video, I'll show you exactly why alkalinity matters and why water with high alkalinity is much harder to shift. All right, that's just about it for this video, but let's dive in a little bit deeper into the science and
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have a look what's happening backstage. Uh, so what we have here is a representation of course of phosphoric acid.
Most of our sanitizers these days like star sand are based on uh phosphoric acid, but it can also be used
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to adjust pH just like lactic acid can. You don't use star sand.
You use more of a pure. It's around 88%age phosphoric acid.
Star's got a whole bunch of other stuff in it. Phosphoric acid is a weak acid.
The reason it's a
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weak acid is that its bonds that hold on to its hydrogen ions are strong. So, a weak acid has strong bonds.
And that makes sense when you think about it because it holds on
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to its hydrogen more than some other acids. A strong acid would have weak bonds and it would just lose a lot of its hydrogen straight away.
Phosphoric acid's a weak acid, so it doesn't lose them straight away. But when we put it into the mesh, one of those bonds can
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break very easily and it can lose one of those hydrogen ions. When you see acids depicted in videos and things just like I did earlier in the video, they show that acids have more hydrogen ions and
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you know bases sort of take away the hydrogen ions. You know, of course, they're not disappearing and they're actually in acids connecting to the water molecule.
So they become actually become H3O.
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It doesn't really happen in brewing, but it can happen with changes in temperature and changes of pH. Phosphoric acid could possibly lose those other two hydrogen ions.
Uh, if we're just talking about in pH, the second ion would drop off at around 7
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pH, I think it is from memory. Uh, and the third one is around 12 pH.
So, really in brewing, we're not getting rid of those ions like that. So mostly in our mesh, we're only losing the one ion and that's that's why it's a weak acid.
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As I said before, a strong acid could dump all those hydrogen ions, you know, as soon as you mix it in. So there's the little bit of science for today.
There's your hydrogen ions. And it's they can sort of go backwards and forwards most of these reactions, too.
So when you see
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a formula up and some of the formulas will only have an arrow going one way so that you know phosphoric acid and water in the mash it loses that hydrogen ion. There is situations where things can go back the other way and often in
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solutions it's kind of a constant thing. they're happening that where they're going backwards and forwards but you know as one's going back another one from somewhere else is is moving over.
So it's not like the pH will be jumping
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around and changing massively. It kind of comes to an equilibrium but yes they are moving backwards and forwards.
Jeez, I need a beer after that.
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Thanks for watching. like, subscribe, share, and all that sort of stuff.
Go and check out my new website. There's not much on it at the moment, but it's where I'm going to be running the giveaways and competitions and things like that.
As I said in the last video, it's much easier to go from a database
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of interested people than than going through all the comments and then sorting it all out. So, just pop your email in down the bottom and whenever I give do a giveaway, you'll be the first ones to hear about it.
A big shout out goes to my patrons. Without them, I couldn't continue to do this.
If you
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haven't seen my Patreon, there's about 500 odd videos on there. There's nearly more than the main channel.
Most of it is just brewery updates, but uh there's a lot of u full uncut um brewing videos and things like that on there where you would have seen me muck around with pH a lot more than you do on the mainstream
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channel. I try not to confuse people on the mainstream channel and see my pH adjustments are going to be different to yours.
But we're going to go through all that sort of stuff in this series of videos. So like, subscribe, share the video.
Um, if you not subscribed, subscribe. Most of my viewers aren't.
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It's really weird when you look at the stats and you see, you know, hundreds of thousands of views and, uh, there's only a very small percentage subscribed and it doesn't cost you anything. Just click that little thing.
But, uh, thank you and I'll see you in the next one. Uh, stay up to date.
Uh, get that click that
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little bell and you'll get the next water video. Um, I'm trying to get them out as fast as possible.
It was going to be one a week. They're probably going to be a little bit slower like than that, especially over Christmas, but uh there's at least another few to come.
There's a few to come. As I said, the
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next one's alkalinity. Really important.
And uh then we're going to dive into the numbers and the styles of beer and all that sort of thing. So, take it easy.
Cheers. It's a Friday here.
I'm going to have a beer. Cheers.
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Keep on brewing.