Knowledge Base
Coffee & Tea Guides
Brew better and explore more — buying guides, how-tos, and explainers for every coffee and tea ritual.
Explainer
Coffee and Acid Reflux: Causes and Gentler Options
Coffee can trigger acid reflux and heartburn in some people because caffeine and its natural acids may relax the valve above the stomach. Here is why it happens, who it affects, and gentler swaps that keep the ritual.
Explainer
Does Coffee Raise Blood Pressure?
Caffeine can briefly raise blood pressure, and the spike is biggest for people who rarely drink coffee. But it fades as tolerance builds, and moderate long-term coffee is not clearly tied to lasting hypertension. Here is the balanced picture — plus who should be cautious.
Explainer
Tannins in Tea: What They Are and Why They Matter
Tannins are the astringent polyphenols that give tea its brisk, mouth-drying grip and colour. Here is what they are, which teas have the most, the iron-timing link, and how to soften a dry, bitter cup.
Explainer
Does Tea Expire? Shelf Life and Storage
Tea does not really expire the way food does — it slowly goes stale. Here is how long tea lasts by type, when it is genuinely unsafe, and how to store it so your leaves stay fresh.
Explainer
How Many Times Can You Steep Tea?
You can steep most whole-leaf tea more than once — usually 2 to 3 times for everyday greens and blacks, and 5 to 8 or beyond for oolong and pu-erh brewed gongfu style. Here is how many infusions each tea type gives, and how to re-steep well.
Explainer
Oolong vs Black Tea: What's the Difference?
Oolong and black tea come from the same plant but split at one step — oxidation. Here is how their flavour, caffeine, brewing and re-steeping compare, and which to choose.
Explainer
White Tea vs Green Tea: What's the Difference?
White tea and green tea come from the same plant but are made in almost opposite ways — one barely touched, one locked in by heat. Here is how they differ in taste, caffeine, antioxidants and brewing, and how to choose.
Explainer
How Long Does Matcha Last? Shelf Life and Storage
Unopened matcha keeps its best quality for about a year, but once opened it fades within weeks. Here is how long matcha lasts, the signs it is past its best, and how to store it so it stays vividly green.
Explainer
How Much Caffeine Is in Oolong Tea?
Oolong tea has a moderate amount of caffeine — roughly 30 to 50 mg per cup, less than coffee and usually a little under black tea, but more than most greens. Here is the rough number, what changes it, and whether roasting really lowers caffeine.
Explainer
Tea and Iron Absorption: What to Know
Tea's tannins can reduce how much plant iron your body absorbs from food. Here's how the effect works, who should pay attention, and the simple timing and vitamin-C habits that keep tea and iron on good terms.
Explainer
Green Tea Before Bed: Does It Help or Hurt Sleep?
Green tea before bed is a trade-off: caffeine can disturb sleep while calming L-theanine pulls the other way. Here is how timing, dose, and sensitivity decide it, plus gentler decaf and herbal swaps.
Explainer
Green Tea on an Empty Stomach: Good or Bad?
Drinking green tea on an empty stomach is fine for many people, but its tannins and caffeine can cause nausea or mild acidity in sensitive drinkers. Here is why it happens, whether morning tea is bad, and how to sip it gently.
Explainer
What Is a Coffee Nap? The Caffeine-Plus-Sleep Energy Trick
A coffee nap is a timing trick: drink a coffee, nap for 15 to 20 minutes, and wake up just as the caffeine kicks in. Here is the science of why it works, how to do it, and who should skip it.
Explainer
Coffee Extraction Explained: Under vs Over
Coffee extraction is hot water dissolving flavor out of ground coffee - sweet and balanced when it is right, sour when under-extracted, bitter when over-extracted. Here is the tasting map and the levers to fix it.
Explainer
Why Is My Coffee Bitter? Causes and Fixes
Bitter coffee is almost always over-extracted. Here is what pulls too much from the grounds — grind, water temperature, brew time, ratio, roast and dirty gear — and how to fix each, with a quick cause-and-fix table.
Explainer
Instant vs Ground Coffee: What's the Difference?
Instant vs ground coffee, compared: instant is brewed coffee dried into dissolvable granules, ground is roasted beans you brew fresh. Ground tastes fuller; instant wins on speed, shelf life and convenience. Here is when each one makes sense.
Explainer
Matcha vs Coffee: Caffeine, Energy and Taste Compared
Matcha vs coffee is really a question of how you want your energy to feel. Here is how their caffeine, L-theanine, taste and antioxidants stack up, and how to choose.
Explainer
Chlorogenic Acid in Coffee, Explained
Chlorogenic acid is the main group of antioxidant polyphenols in coffee. Here is what it is, how roasting changes it, its role in flavour, and why it powers the green coffee buzz.
Explainer
Is Black Coffee Good for Cholesterol? What Your Brew Method Changes
Black coffee contains no cholesterol, but how you brew it matters: unfiltered coffee's cafestol and kahweol can modestly raise LDL, while a paper filter traps most of them. Here's the filtered-vs-unfiltered story.
Explainer
Is Coffee a Diuretic? Does It Dehydrate You?
Is coffee a diuretic? Yes, but only a mild one. Here's why moderate coffee doesn't dehydrate you, why regular drinkers barely notice the effect, and how a daily cup still counts toward your fluids.
Explainer
Why Does Coffee Make You Poop? The Gut Science
Coffee makes many people need the bathroom within minutes. Here is the real reason, from the gastrocolic reflex to gut hormones, plus why decaf does it too.
Explainer
Does Coffee Cause Anxiety? What Caffeine Really Does
Coffee does not cause anxiety by itself, but caffeine is a stimulant that can trigger or amplify jitters, a racing heart and restlessness in sensitive people. Here is how caffeine and anxiety overlap, who should be cautious, and gentle ways to cut back.
Explainer
Guava Leaf Tea: What It Is and How to Make It
Guava leaf tea is a caffeine-free herbal infusion made from the leaves of the guava tree — here is what it is, how it tastes, how to brew a cup at home, and the traditional uses people talk about.
Explainer
Rooibos vs Green Tea: What's the Difference?
The real difference between rooibos vs green tea is the plant: green tea is a caffeinated true tea, while rooibos is a caffeine-free South African red bush tisane. Here is how they compare on taste, caffeine, antioxidants and brewing.