Coffee and alkaline active water
Manfred M.: In your service manual, you show coffee as an acidic drink on a beverage comparison table. There is a significant difference between filter coffee at around pH 5 and soluble Arabica coffee at around pH 6 - but I don't like instant coffee! Can you tell me whether it is of any use to filter the coffee with alkaline activated water?
- These are almost existential questions for many people because they want to give up everything but coffee. Therefore, I receive a lot of inquiries about this topic and I would like to answer them in detail.
- Yes, coffee is acidic, although different. Robusta beans, which are added to filter coffee blends - they are cheaper - are the most acidic, Arabica coffee is more alkaline than most mineral waters. With regard to the acid/alkaline balance, it is better to buy the more expensive Arabica varieties.
- I'm basically talking about black, unsweetened coffee here. Additions of milk, cream or sugar can of course change the values depending on their specific properties.
- The preparation method also plays a role in the pH value. Turkish coffee/Greek mocha is the most acidic. If the coffee powder is boiled together with the water and not separated, most of the acids pass into the water. Since sugar is usually added to this method of preparation, the sour taste is masked. Filter coffee also has a relatively long contact time with the powder, so it is correspondingly more acidic. Espresso/Café Crema has the least contact time, so the acid load is correspondingly low. Instant arabica espresso is optimally mixed by experts and dissolved immediately. The pH value varies with the water used.
- If you use alkaline active water, you can only slightly increase the pH value in any type of preparation, as coffee is a strongly acid-buffered liquid whose acidic character can hardly be disturbed by water, similar to stomach acid. The following also speaks against making coffee with alkaline activated water: Fresh alkaline activated water is richer in minerals and harder than the original tap water. Therefore, you need to descale your kettle or coffee machine more often than usual, as more minerals are precipitated when heated. Even with normal tap water, minerals fall out as scale when heated.
- It would therefore make more sense to then mix the precipitated minerals back into the coffee powder. With a little trick, you can buffer the active water more by mixing a tasteless, calcium-rich mineral powder (1/2 teaspoon) into the coffee powder. For example, for a Café Crema from the espresso machine there is a difference of around 0,5 pH in favor of the buffered coffee powder. The crema also becomes stronger. There's no arguing about taste, but coffee connoisseurs know that calcium is an excellent flavor and aroma carrier and therefore prefer hard water in contrast to making tea. The trick with the mineral powder is particularly helpful if you have very soft water at home.
- This actually answers your question, but I would like to point out that acidification is not the main issue with coffee. Even in the worst case scenario, coffee is not as acidic as most other consumer and pleasure drinks and is not consumed in such large quantities as, for example, cola, fruit nectars, lemonades or beer. We know that even a single cup of coffee can lower the saliva pH, but this can be quickly compensated for if you continuously drink no more than 1 to 2 cups a day - espresso is best.
- The real health issue when it comes to coffee is its antioxidant content. Although many of the antioxidants are lost when green beans are roasted, many antioxidants are still retained, especially when the more expensive varieties are roasted gently and slowly.
- Americans are not exactly known for their healthy and balanced diet. Fruits and vegetables, as suppliers of antioxidants, are the exception on the menu. Therefore, according to a study from 2005, coffee is actually by far the most important source of antioxidants in the population there. (Source: Americ. Chem. Society, http://chipsa.com/coffee_O2.pdf). Fortunately, Europe has a more health-oriented eating culture, so coffee can only be viewed as a luxury food and plays no role in providing antioxidants.
- The antioxidant power of alkaline activated water, like that of coffee, is reflected in its low or even negative levels —> Redox potential. We measured values between + 157 mV (Espresso Machiato cup from the refrigerated shelf) and - 285 mV (instant espresso, alkaline activated water pH 9,5 / -350 mV, heated using a microwave) on various coffee samples. With a normal heating method (electric stove, coffee machine, kettle), the use of alkaline activated water does not reduce the redox potential of coffee, as all heating methods apart from the microwave, which is tailored to water molecules, apparently destroy the redox potential more quickly. After all, we measured redox potentials of an average of -70 mV for freshly ground Café Crema made with an electric espresso machine - regardless of the water used.
- If you just want a cool, caffeinated soft drink, I recommend my method: Make two cups of espresso with 1/2 teaspoon of added mineral powder (e.g. calcium carbonate) in the machine. Carbonate fresh alkaline activated water in the soda machine. Pour the espresso into a glass with 0,5 liters of activated soda water. Add ice cubes if desired. Delicious, very rich in antioxidants, slightly carbonated, bitter and aromatic. This is anything but “cold coffee”, it’s Cola for coffee lovers! For me, of course, without sugar or sweeteners.
- Since the antioxidant effect of alkaline active water depends primarily on the dissolved hydrogen, I wanted to know how much hydrogen is retained in the espresso machine after the brewing process. Unfortunately, the usual measuring drops (—> hydrogen measurement) cannot be used due to the strong color of coffee. However, you can at least roughly see from the results of the ORP measurement that a very hydrogen-rich starting water (after the water ionizer, boosted with the —> Aquavolta hydrogen booster) also has the lowest redox potential (mV - CSE) in the end. From left: TAP = tap water. EAW = alkaline activated water. EAW + B = boosted alkaline active water (3,3 ppm dH2).
- Finally, coffee lovers might be interested in the question: What happens if I chemically spice up my coffee by throwing a hydrogen tablet into the finished coffee? I also tested this and used two different hydrogen tablets A and B, whose chemistry is based on magnesium (metallic) and malic acid. Result: Tablet B, which makes the coffee unpalatable sour, scores with a lower redox potential. Tablet A, which is only mildly acidic, increases the aroma and also improves the redox potential.
- Both tablets damage the originally very beautiful foam of the “Tchibo Caffè crema mild” coffee made with an Italian espresso machine from Delonghi.
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