Blog : coffee brewing

Water and Chemistry

Water and Chemistry

This article was originally written by Matt Campbell for the membership of Coffee Props.  Please visit www.coffeeprops.com to join the conversation and be a part of the community!

So much focus has been put on the coffee itself, and rightfully so. The grind size, consistency of grind, freshness and quality of the bean, roast quality and method of brewing are all important factors when considering the end result of your brew. Traditionally when we would talk about water we would be discussing water to coffee ratio, temperature of brew water, speed and type of infusion method, and filtration. While these factors are all important, recent studies have broadened our understanding of our water.

 

What can be so complicated? Water is H2O, right? Well, yes; and no, not always. Without getting too deep into the physics and chemistry of it all, water is made up of hydrogen and oxygen atoms, and the liquid we all know and love is capable of dissolving all sorts of other molecules. The makeup of water depends on a multitude of factors and conditions, and it is a complex array of chemistry and physics. Each water sample can react differently with its surrounding environment, and it is no different when we heat it and pour it over a bed of coffee.

 

It has been shown that magnesium (Mg +2) and calcium (Ca +2) are important to extracting flavor from coffee. These two atoms readily dissolve in water to create ions. These ions have a charge, which reacts chemically with flavor in the coffee to extract it into solution. Adding the sum of these two minerals together to calculate their abundance in parts-per-million (PPM) will give us an idea of general hardness, or GH.

 

On the opposing side of these ions are carbonate ions (HCO3 -1), which is more commonly referred to as the alkalinity or buffering agent (KH). This also contributes to coffee flavor, but it must be kept in check to prevent undesirable changes.

 

Although there are other minerals and ions in solution, the three mentioned above are the most important factors that impact flavor. These ions must be kept at the right level of hardness, but they must also be in proper quantities relative to each other. The preferred ration seems to be 2:1 in favor of the general hardness when the GH is around 100 ppm.

 

Believe it or not, that was actually a pretty dumbed down version of the whole story. Although these are just the basic facts, there is a whole textbook of information called, “Water for Coffee.” If you are they type that needs to know more, there is no more relevant and thorough information available. It isn’t exactly an easy read, but it is articulate and complete.

 

All this fantastic information has been made available recently, but now what can we do with it? Sure, we can purchase titration test kits and expensive filtration solutions to make the perfect water for coffee, but for the average household this is not a feasible option. Is all lost?

 

Not quite. The chemistry may be complicated to understand, but some very smart people have broken it down for us. Matthew Perger, WBC all-star and coffee guru has been dropping knowledge for us, so I will yield the floor to his recipe for perfect water:

 

Water Recipe:

 

Based on instructions from Matthew Perger, and the book Water for Coffee

Ingredients: Sodium Bicarbonate (aka baking soda); magnesium sulfate (Epsom salt); distilled water

NOTES:

  • Distilled water, spring water, and purified water are not the same. It must be labeled distilled for this to work.
  • The Epsom salts must be unscented, and read magnesium sulfate. MgSO4

 

INSTRUCTIONS:

 

To make concentrate:

  1. Add 8.6g baking soda, and 25g Epsom salt to 500g distilled water. This is your concentrate.
  2. Shake this concentrate until it is all dissolved.

 

To make perfect coffee water:

  1. Place 500g of distilled water into a clean glass container.
  2. Carefully mix 2.5g of CONCENTRATE into the distilled water.
By the Numbers

By the Numbers

Home Coffee Brewing: By the Numbers

 

This is the fourth in a series of blog posts that will teach you how to confidently brew exceptional coffee at home.

 

If you have been following the last few blog posts, you should be well on your way to brewing great coffee in your kitchen or office. You may have already improved your quality significantly, so lets delve deeper and see what else we can do to get the most out of our brew.

 

There are numbers involved in every part of life, and coffee should be no exception. With coffee brewing we are always thinking about things like water to coffee ratio, temperature of water, and contact time. All of these add up to a great experience, or a tasteless disappointment. Let’s get down to the nitty-gritty and make the numbers work for us.

 

There are lots of instructions out there intended as guides to help you measure out the coffee for your brewer. These are usually measured in tablespoons per cup of water, and are relatively accurate for most coffee drinkers. If you have made it this far into the blog, you are not like most coffee drinkers, so you will want a scale that can measure in grams, or 1/10th grams. Why? I’m so glad you asked.

 

Different beans and different roasts have different densities. One tablespoon of a light roast can weigh 10 grams, while one tablespoon of a French roast will weigh as little as 7. That is a 30% difference! The only way to account for the many (many) variables that make up a coffee’s weight is to use a digital scale. Use a scale, and watch your quality improve instantly.

 

Water is a little bit different. Although water changes from one location to another (mineral density, contaminants, etc.) it is relatively the same across the board. 1ml of water = 1 gram. Once you figure out how many grams of coffee you want to brew, you can measure the water in grams and be almost perfectly accurate.

 

Brewing in an automatic home machine:

 

So what do we use? We have found that with out water, we need about 25 grams for 12oz of water. This is about 11-12 grams for every 6 ounces you want to make. This number can change depending on your water selection (but you already know to use mineral water, right?)

**(Many coffee brewing machines consider 4 fl oz to be a cup. We recommend you measure how much water it takes to get to the “10 cup” mark on your coffee pot to make sure it is 60 fl oz instead of 40 fl oz. Adjust from there to make up for any discrepancy.)**

 

Water temperature is another big factor in the brewing process. Many home coffee makers do not get the water hot enough to properly extract all of the flavor out of the coffee. We use water that is dispensed from a heater at 205º. The easiest way to assure that you are getting the full flavor you deserve is to check your water temperature. If it does not come out within a few degrees of the 205 mark, then it is time to either adjust (if your coffee maker allows) or search out a new brewing method. Many home baristas will boil water in a special pouring kettle and begin the brew a few moments off the boil to ensure they are in the proper temp zone.

 

The final hurdle for this post is the amount of time that the coffee and water are in contact with each other. The longer the water interacts with the coffee the more particles are extracted, both good and bad. If the contact time is too long the coffee can extract lots of bitter tastes and ‘tannins’ that contribute to a poor quality cup. To short of a contact time, and the cup can be unbalanced or too sharp. Most people recommend between 3-4 minutes of contact time for a 12 fl oz cup of coffee. Although this is usually reserved for manual pour-over style brews, you can at least get an idea of how the contact time may be affecting your automatic brewer.

 

Up next:

Home Coffee Brewing: Pour Over Methods

The Grind

The Grind

Home Coffee Brewing: The Grind

 

This is the third in a series of blog posts that will teach you how to confidently brew exceptional coffee at home.

 

So far we have discussed the importance of the two main ingredients in coffee; the beans themselves, and the water that brews them. How the beans are ground is just as important to coffee brewing as the water and coffee selection. Slight variations in the grind setting can have dramatically different results in the final product. Let’s get down to the details, and help to really fine-tune the process.

 

To grind, or not to grind?

 

When buying your beans, you have the choice of buying pre-ground or whole bean. At a micro roaster all of the beans are likely whole bean, and your barista will grind them for you at the time of sale if you need. Is there a difference in quality one-way or the other? You bet.

 

Why grind at home? A few days after the coffee is roasted, it begins to lose flavor. When the beans are ground the surface area of the beans is increased exponentially, allowing more of that flavor and aroma dissipate and escape! Most reputable coffee shops will only grind their beans moments before they start the brewing process to retain that flavor you have come to expect. Grinding your beans at home will dramatically increase the freshness and flavor profile of the coffee you have brought home to enjoy. There are many types of grinders out there, so which one is best?

 

At the entry level, you can find cheap blade grinders which use a propeller like action to chop up the coffee. They are entry level grinders that allow you to grind only what you need for the coffee you are making at the time, but they fall short on another important quality; consistency.  These grinders have a major fault when it comes to grind uniformity.  They create lots of boulders (huge chunks) and fines (powder) at the same time.  Although we used to carry them on our shelves, we have replaced them with a line of manual and electric burr grinders.

 

A burr grinder will allow for more control over the coarseness of grind, and provide for a much more consistent result. Most burr grinders will have a ‘hopper’ or chamber where the whole beans will be stored and fed into the grinder as needed. Quality and consistency are the benchmarks that should be expected from most burr grinders. There is a wide price range in this category that varies depending on features and manufacturer reputation. If there is room in your budget, and you are looking for a drastic improvement in your home brewing, burr grinders are the way to go.

 

When it comes to choosing the proper grind for your coffee, everything will depend on your brewing method. There are as many ways to brew coffee as there are countries enjoying that coffee, and each one comes with its own unique style and grind. From the French Press with its course grind, to the Turkish coffee and its (almost) powder-like grind, there are limitless options and methods to prepare the beans for brewing. You should ask your barista about how to best grind the coffee for your particular method, and then experiment a little bit until you find that ‘sweet spot.’

 

So our best advice to you is to spend a few extra dollars and get a grinder. You will notice an immediate improvement in your brewing quality, and get more enjoyment out of those specialty beans you are buying. Grinding fresh is one of the most simple things you can do to step up the home coffee quality.

 

Up next:

Home Coffee Brewing: By the Numbers

 

 

Home Coffee Brewing:  The Water

Home Coffee Brewing: The Water

Home Coffee Brewing: The Water

 

This is the second in a series of blog posts that will teach you how to confidently brew exceptional coffee at home.

 

We have already touched on the importance of using fresh delicious coffee for your home brewing, and now we will cover the next most important ingredient: the water.

 

In properly brewed drip coffee, water makes up more than 98% of your drink. If you are not using great water, you are already limiting your ability to enjoy excellent coffee at home. Depending on your source of water there can be many contaminants that impart flavor, odor, or other undesirable characteristics directly into your cup.

 

Water is one of the most important considerations to professional coffee shops, and most will spend hundreds or thousands of dollars to test their water and develop a filtration plan that will adjust the water to perfect the coffee. Baristas and espresso technicians are continually tasting, testing, and evaluating the quality of their water to know when the filters may be in need of a replacement.

 

There are dozens of ways to filter water and every process has its drawbacks. The best place to start to evaluate your needs would be to get a water report from your local water utility. They are required to file public reports of water content and contaminants, so this may give you a good starting point of what your water may be like. If you are on well water, there are usually test kits at local hardware stores.

 

Although reverse osmosis (RO) is all the rage in home filtration systems now, this process strips the water of all contaminants, even the minerals that give water its clean and crisp taste. These minerals also help during the extraction process and allow the water to remove the delicious coffee flavors and aromas. RO is almost too pure of a filtration system, and we do not recommend it.

 

Another option is the activated charcoal in common kitchen appliances (Britta or Pur). These do help to remove the odors and flavors that we don’t like in our coffee, like chlorine or sulfur. Using these will absolutely improve your brewing, but they can be hard to remember to change the filters on time, and the filters can become overly saturated with the contaminants and become less effective.

 

The best system we have found is a triple filtration system. They consist of two charcoal block filters, and one descaling filter. These systems keep the good minerals to ensure proper extraction and flavor, and they remove a surprising amount of the negative components. This is not very practical for most people, however. These systems are somewhat expensive and they take up a good amount of under-counter space.

 

The most practical option for most people is to buy their water from the supermarket. For between $0.99 – $1.25, you can buy fresh and delicious water and keep it dedicated for your coffee. Using name brand waters may improve flavor further because the big companies tend to have a tight control on their mineral content.

**If going this route make sure you buy the spring water, not distilled water! Distilled water has the same flaws as RO!**

 

Now let’s bring it all together. Although it is not often thought about, water is just as important to the coffee brewing process as the coffee itself. There are tests to find out what your water content is, and there are filtration solutions that can be tailor fit to your results. This could be a good option for the consumer who wants to get perfection from their home brewing methods, but they can be expensive and time consuming.

 

For most of us that just want a few simple tips and tricks to improve the taste of the morning coffee, we recommend trying and tasting the differences. Most people will find that just using a bottle of spring water from the grocery store will have a significant impact on their coffee.

 

The coffee world is full of opinions, but the only one that matters is yours. We write these guidelines to help you avoid the pitfalls we have discovered through years of experience. You should feel encouraged to explore and experiment for yourself to find a combination that works!

 

Up next:

Home Coffee Brewing: The Grind

Home Coffee Brewing: The Coffee

Home Coffee Brewing: The Coffee

This is the first in a series of blog posts that will help teach you how to confidently brew exceptional coffee at home.

Although there are only two main ingredients in making coffee, there are dozens of variables that can have an effect on the final cup.  Over the next few posts, we will dive into some of the factors that can be adjusted to help you brew some great coffee in your own home.

The first thing we have to consider is the coffee beans you are using to brew your cup.  As with most things in life, there are endless choices when it comes to selecting your coffee.  Coffee ranges from pre-ground commercial mass production, to rare small batch specialty lots.

If you want a coffee that is full of flavor but is a huge step up from your generic big-box variety, then you will probably be looking for what the coffee industry calls “Specialty Coffee.”  This is a term that is used to describe coffee that is a cut above the rest.  You wont find this term on any of your typical well known brands on the supermarket shelves.  There is a whole world within the coffee industry that only deals with “Specialty Coffee.”

What is specialty coffee?  90% of the coffee beans grown and consumed are considered ‘commercial grade.’  This means that they are just average, and targeted to the consumer that only wants caffeine in a cup.  That other 10% of coffee is something special.  It is carefully selected from the entire crop and put aside for purchase by a more selective consumer.  This is the quality of coffee that Branch Street uses, and we know that it makes for a better end product.

If you want a more enjoyable coffee get rid of your commercial coffee grounds.  So where should you be getting that specialty coffee from?  Seek out a knowledgable and local coffee roaster.  Buying fresh roasted specialty coffee will be the most important upgrade in quality you can make.

Roasting is the process of changing the green, or natural coffee bean, into the brown and delicious drink we all love.  Anyone can roast coffee, but it takes someone with special knowledge and training to do it well.  There are many factors along the way that can either make a coffee amazing and full of flavor, or flat and unimpressive.  Even worse, it could taste baked or burned.  No one wants a boring cup of coffee, or a mouth full of ash.

Roasting coffee is a lot like cooking.  Two cooks with the same ingredients can have to completely different products, and experience can make all the difference.

Not only does it have to be expertly roasted to ensure the flavor and unique characteristics are preserved and accentuated, but it needs to be fresh to really impress.

Once a coffee is roasted, it begins a process called ‘degassing.’  Degassing is the bean releasing carbon dioxide, and opening up flavors within the bean.  Most coffees are best when they have rested for a day or two after roasting.   If they are not protected from oxygen and temperature changes, it will quickly go stale and lose all of that incredible flavor we worked so hard to find.  Look for a “Roasted On” date on the bag.  If you can’t find one, you have no idea how long that bag has been sitting on the shelf.

If you make the decision to buy from a local roaster you are taking the first step to ensure that you are going to be brewing high quality, fresh coffee at home.

Ask to taste the coffee you will be buying.  A reputable roaster will be more than happy to brew a cup for you, and let you drink it how you see fit.  Add your own milk add sugar if that is how you normally enjoy your coffee.  Make it how you would drink it at home, and see if you want to commit to a whole bag.

Talk to your barista about the coffee.  Your barista should be knowledgeable about all of the coffee they are serving, and they should be able to guide you to a coffee you will love.  Tell them the flavor traits you love, and let them find a coffee that will fit your needs.  Your local roaster should have a wide variety to help you find your way.

At Branch Street Coffee Roasters we are committed to the whole process, from bean to bag.  All of our coffee is roasted as we need it, and packaged in sealed bags with one-way valves (to allow CO2 to escape, and keep oxygen out).  The beans are kept in a temperature-controlled room out of the sun until it is sold to you.  We do not sell or serve any coffee that is past our date standards, so you can be confident that you are bringing home exceptional, fresh coffee.  Come by and taste the coffee before you decide if it is one you will love.

Up next:

Home Coffee Brewing: The Water