How can some people drink five cups of coffee a day without ascending to another plane while others just need a whiff of espresso to send their bodies into a buzz? Genetics play a huge role, according to a new report by Dr. JW Langer, which breaks caffeine imbibers into three sensitivity groups.

Have you ever found yourself chugging coffee to stay up late studying, but then when it's time for the exam, your mind is foggy with fatigue? Researchers from the US Army have developed an algorithm that can predict the energy peaks and valleys that come from drinking caffeine, and in turn, created a web-based tool that helps you predict how alert you can expect to be based on your own sleep schedule and coffee habits.

As a former barista and insufferable coffee snob, I long believed coffee pod machines were beneath me. My kitchen cupboards are like a museum dedicated to the pursuit of extracting caffeine from a bean, from cold drip to Moka Pots, Aeropress to Vario. No method was too time consuming or pretentious for me to try.

Nothing livens up a hot afternoon quite like a cup of iced coffee. Trouble is, a lot of the iced coffee out there is just stale, leftover hot brewed coffee that's been chilled, or cold brewed coffee with a much different taste. Enter Japanese iced coffee - the best of both worlds.

When you're drinking a hot beverage, you want that beverage to remain hot. Of course you do! You're a human being with needs. Sadly, it won't - you can't fight the second law of thermodynamics; even if you prime your cup first, eventually entropy will have its way. Eventually, you'll take a swig of your coffee or your tea and get a mouthful of lukewarm disappointment. If your 9am cup tastes like a brand new day, full of promise, then your 10:15 dregs remind you that it's seven hours until you can start drinking.

Disclaimer: This isn't so much a "tiny hack" -- a tag we at Lifehacker use for simple tricks -- so much as a "tiny pleasure." It's something that I do every day that makes me happy. It doesn't improve anything except the flavour of my mornings, and everyone should give it a shot. (That's an espresso pun right there.)

When we last rounded up our staff's Weekly Upgrades, our editors were email batching, meal prepping, cleaning, and scheduling in extra downtime.

During a trip to Dublin a few years ago I befriended a group of older Irish women at a bar one afternoon, as one does. At some point during the conversation, it came out that I had never had a true Irish coffee. Seconds later they made sure I had one in my hand and I was hooked.

I love coffee, but my mind and body are both easily overwhelmed by caffeine, so I often find myself with a cup or so of leftover java (do people still call it that?) by the time noon rolls around. It's usually too stale for drinking by then, but it still has its uses.

Summer is behind us, but I suspect more than a few warm days are in store for us on the march through autumn. You know what's great on hot days when you need a caffeine hit? Cold brew. Back in 2013, I wrote about making your own at home and although the process hasn't really changed, I do have some updated thoughts.

Coffee. Good? Bad? The verdict is constantly flip-flopping. Hey, as long as you consume it in moderation and you know, don't subsist entirely on the caffeine-infused beverage, you should be OK. But what if all you did was drink coffee for a day? No food. No water. Just coffee.

Bad coffee is the best coffee. Or less cryptically: The lower you can set your standard for acceptable coffee, the happier you'll be.

Brief news items of note for Lifehacker readers, including: BioWare faces uncertain future, most overused words on Australian LinkedIn profiles, Asutralian review of the new Nespresso Vertuo Plus.

I enjoy starting the day with a coffee. That little kick of caffeine inspires me to get out of bed and get to work on time. I drink it via my mouth, as is intended, however, for about 100 years, the idea that coffee enemas can 'detoxify' your colon has existed.

There is no evidence to suggest that these work at all.

A recent headline in the Australian newspaper claimed “A short black a day can keep heart attack at bay”. Is this more good news for coffee lovers, or a case of be careful what you read?

Happy Black Friday, my babies, and welcome back to 3-Ingredient Happy Hour, the weekly drink column featuring super simple yet delicious libations. You have, by now, made it through the week, and for that, you deserve a drink.

Cold brew coffee has been the frigid ice queen of the caffeinated world for some time now, but I think it's finally safe to admit that it just isn't for everyone. Not only does it usually have more caffeine than other coffee (which is bad for those of us with anxious little hamster hearts), but it has a very distinct flavour that is not appealing to all people, because not everyone likes the same things.

The best way to save money on Starbucks is to make your coffee at home. The second best way is to buy it somewhere cheaper. But the third best way is to hack your Starbucks order to pay less for the same (or similar) drink. Some hacks are innocent; others less so. Here's a compilation of the best Starbucks hacks from over the years.

I'm usually not a huge fan of putting carbon dioxide in my coffee, but I'm willing to make some exceptions. For example, cold brew on nitro is great; the bubbles are nice and small and give the coffee a smooth, creamy mouthfeel. Plus, I've tried some fancy coffee soda water things and found that they mostly just cause oral confusion -- see exhibit A below, which was the most perplexing, yet delicious thing I've ever put in my mouth.