A cup of coffee can commit two cardinal sins: too bitter, or too boring. Cups of coffee at restaurants indifferent to detail often are one or the other. I have better luck at coffee shops, and recently have had such great luck at two little local businesses that I wanted to write about them to let you know.

First is One World Roasters, 967 High Street, East Haven, which earlier this summer gave a free workshop on cold brew. The folks there are passionate about their coffee, dedicated to doing it right, and happy to share knowledge on how to make the best of their beans. They have another class coming up Saturday, Sept. 23 at 10 a.m. on Coffee & Sustainability from Seed to Cup: Following the Journey of Coffee. (www.oneworldroasters.com/coffee-events.html#/)

The other one is Camper Coffee, currently staged at School Street in Madison, but only until Aug. 27. So if you take nothing else from this story, and you live in or around Madison, you might want to check out Camper Coffee before they close up for the summer. They are equally passionate and creative about the drinks they are serving.

Both One World and Camper Coffee are just a few minutes off of I-95, so if you are passing East Haven or Madison before or after work, or on your way or back from the beach, both are worth a quick side trip.

Here are a few things I learned from One World Roasters about cold brew, a process that retains all the complexity of a good coffee bean while avoiding the pitfalls of bitterness, and what I learned from Camper Coffee about cold foam. They explained how to make it in a way that, when it’s dolloped carefully on a good cup of coffee, it does not dilute that coffee but rather, allows the coffee to slip underneath, making space for both the complexity of the coffee and the sweetness perched atop.

Cold Brew

In a free workshop earlier this summer, Eric Ciolino, the co-owner and chief roaster at One World Roasters explained how the process of cold brew creates a fundamentally different taste profile than traditional hot brewing methods. So that makes it different than iced coffee, which is usually made from hot coffee that is then cooled down and served over ice.

“There are three advantages to cold brew,” Ciolino said. “It is less acidic. It is smoother coffee. And you can brew large quantities, say at the beginning of the week, and it can last 12 to 14 days. If you want hot coffee, you can just heat it up.” It also tends to have somewhat less caffeine.

Cold brew heated up maintains its smoother taste profile. Coffee brewed with hot water, on the other hand, when it is reheated, tends to get even more bitter. “Hot water tends to bring out compounds that don’t get drawn out with cold water,” he says. This is not to say that some of us might prefer the complexity and taste profile of coffee brewed with traditional methods. It’s just that having cold brew in your repertoire gives you more options for both a straight coffee drink and flavored coffee drinks.

Variables that you can play with, when making cold brew, include grind size, filtering method, and brew time. “If any of those fluctuate, you’ll get a different outcome,” he says. He recommends a burr grinder that will give you a consistent outcome every time. The filter can be anything from a cheesecloth to the metal filter in a French Press.

The key is to experiment, he says. “When you try it at home, don’g think you’ll get it perfect every time,” he says. He recommends starting with about 150 grams of coarsely ground coffee to about 4 ½ cups of filtered tap water. Brew it, whether in a mason jar or your French press, from 10 to 14 hours. Then filter it. Those four and a half cups of water could yield up to 16 cups of coffee, once you dilute it after its brewed.

“Grind, brew time, filter, you can play around with these,” says Scott “Pepe” Bodnar, one of his employees, who gave the workshop with Ciolino. How do you know when you have it right? “When you sip your coffee and smile,” says Bodnar. “That’s what you want.”

Cold Foam

At Camper Coffee, you can get yourself a straight cup of hot brewed delicious coffee with beans roasted by Ryan MacKay, who also works in the little camper with Matt Beckoff. Beckoff usually is front of house, tending the register and taking the orders.

While the coffee itself is delicious, their coffee drinks are delicious and so fun. They also have an outstanding decaf, which means I can indulge in their drinks all day. My favorite is their Stormy Mornin’, made from cold brew, house-made Earl Grey lavender simple syrup, and a rose cold foam.

Ah, that rose cold foam.

I asked Beckoff how they made it and he showed me, using an off-the-shelf Zulay frother, and a Rose simple syrup they got from Wäbry. The rose syrup is the only one they buy, they make all the others themselves.

In a metal frothing cup, he put in a squirt of the rose syrup (I’d say it was maybe about a scant half teaspoon), then he added one part non-fat milk, and two parts heavy cream. Then he stirred and spinned the frother, stirring, and spinning to create the foam. “They key is that you want to be able to sip the flavor of the coffee under the foam,” he says. Sometimes he makes the foam with just a touch of vanilla extract, no sugar. “The milk and cream are naturally sweet, so sometimes just that is enough,” he says.

Find out more about One World Roasters at www.oneworldroasters.com/. Find out more about Camper Coffee at www.campcoff.com/.