According to statistics from the USDA, nearly 900 million gallons of ice cream is produced in the U.S. every year. Summer is the unchallenged season for peak ice cream sales and eating—no doubt due to the combination of hot weather and tradition.

But for those who make ice cream, it’s a year round operation and a full-time job. In Vermont, Ben & Jerry’s has been churning out ice cream for nearly 40 years. The company’s humble beginnings trace back to a single scoop shop in a renovated gas station. It has since been acquired by Unilever, and now ranks as one of the top ice cream vendors in the U.S. Ben & Jerry’s made news this year when it threw its support behind its home-state presidential candidate Bernie Sanders, releasing a limited run flavor called “Bernie’s Yearning.”(The eating instructions involved breaking the top 1 percent of the pint—a chocolate disk—and mixing it into the 99 percent plain mint ice cream beneath.)

Althea Sherwood has worked at Ben & Jerry’s for 35 years. Sherwood is a manufacturing operator at a plant in St. Albans, Vermont. I talked to Sherwood about the many challenges of making ice cream. A lightly edited transcript of our conversation follows.

Bourree Lam: How long have you been with Ben & Jerry’s?

Althea Sherwood: I've been with the company for 35 years. I started at the garage—I was a scooper. Then, I worked on Cherry Street, scooping ice cream. Then, I worked at the various plants that were opening up—pretty much all of them, except for the Springfield plant—working in production and mix making. I was a coordinator, a supervisor of mix making, an inventory controller. I worked in logistics, in the warehouse, I stacked ice cream, I shipped ice cream. What else did do? I was the first milk pasteurizer in the state of Vermont. I've been pretty much everything here. I was a mixer of cream and condensed sugar, and all that kind of stuff. I was also a tour guide.

Lam:  And now, you're in production. What does that involve?

Sherwood: I've been doing this job for three years. Right now, that involves making the ice cream. I'm on the floor. Actually, I'm putting the ice cream in the cups and the pints, and sending them down the line. I'm running all the machines.

I'm actually running a line, being the lead. I'm the person that makes sure that all the wheels are greased, everybody's doing their job, and everyone knows what they're doing. If there are any issues, they come to me, and I go to the coordinator. If there's a problem, I will help them make the decision to shut the lines down and try and fix the problem. Or see if we can fix it as we're running, or get maintenance involved, that kind of stuff. I'm actually running the machines as well.

Lam:  Which machines do you work with, and what part of the process is your line?

Sherwood: We get this mix from these big silos, and they get into these vats, and they're flavored with whatever flavor we're running—say, cookie dough. We'll flavor the mix with the cookie-dough ingredient. Then, it'll run through these pipes into these freezers, and it'll make it creamy.

Then we run them into these machines called fruit feeders. That's where we'll put the cookie dough in. At the same time, the ice cream's running through these pipes in the freezer, the cookie dough comes through the fruit feeders and drops into the pipes. Then it dumps into, what we call a filler and what that does is automatically fills four pints at a time. Then, it brings it down the line and it gets a lid put on it.

I run all these machines. When it goes down the line, it will then go on a conveyor, and go through a check layer, and it gets printed on the bottom, and into the freezer. It will go through a spiral freezer where it gets hardened. Then, on the other end, it comes out and it goes upstairs to be put into sleeves of eight pints. It's called bundling.

Then, it goes down another conveyor into these robots that will pull them off. They'll put them on pallets, and they'll stack them so high. Then, one of the guys out back will take them off the line in a fork truck, and they'll put them in a big freezer. Then, from there, they'll pull them out of the freezer and get shipped out, and put on a frozen truck.

Lam:  What kind of problems can occur?

Sherwood: We run everything based on certain specs. If we're not within them, there's something going wrong with some part of the line. It could be that the freezers aren't incorporating enough air, or something like that. We have to figure out why. We'll have to shut the freezers down, and get maintenance involved. They'll go through the freezers and find out why we're not getting enough air to these freezers, so that we can make the ice cream in spec.

Same way with the fruit feeders. If they're not running right, then we’ve got to find out why. What might happen is, something gets plugged. We've put too much in it, and the flow of ice cream isn't going through the pipes fast enough to pull all that cookie dough through the pipes, so it's just clogging. There's so many different pieces to the fruit feeder that it'll clog it up. There's blenders. There's augers. There's all kinds of stuff.

Lam: Are there certain flavors that are harder to make because of clogging or other problems?

Sherwood: Yeah. Your ingredients have to the be a certain temperature. Your ice cream has to be a certain temperature. If your ice cream's too cold, it won't run it. If your ingredients are too soft, it would just make mush. Like, Half Baked is really hard to run if your ingredients are too soft. There are some flavors that are really labor intense. Like, Cake My Day, was an awful flavor to run.

The frosting for Cake My Day had to be a certain temperature to stay in there and make it look right, and keep it swirled in the ice cream correctly. If that wasn't the right temperature, and the ice cream wasn't the right temperature, then it wouldn't sit in there right. You would have to shut down and figure out what to do with that. If it was too cold, you couldn't do it. If it was too warm, you couldn't pump it. If the pumps that we were using wasn't feeding it fast enough, we'd have to shut down and find out how we can make it feed it faster. If the pipe length wasn't the right width, or the right length, then we'd have to figure that out. There's a lot of math to it.

Lam: Are the limited flavors, like Cake My Day, particularly tricky?

Sherwood: Well, it's not so much that it's hard, it's the new flavors that we haven't run, that we have to try and figure out … It depends on what R&D comes up with.

Lam:  You've been at many different roles at the company. Is that usual at Ben & Jerry’s, or was that just your path?

Sherwood: That was just my path. People come and go; they do different things. There are lot of of people who have been with the company for a long time.

When I started, the company was really small. You didn't have a lot of choice in what you were doing. I also went to college for business management, so that kind of fit in. Then, as the company grew, there were more opportunities to grow with that. My biggest path was more in the mix part of it, and learning how to pasteurize it, and how to make all that stuff. Ben & Jerry's really was big on sending me to school, and teaching me how to do that.

Lam: Tell me about your pasteurization qualification.

Sherwood: When we first started, we used to get our mix from The University of Vermont. They used to make it for us. As the company got bigger, they couldn't make it anymore because they couldn't keep up with our demands, so we had to learn how to do it ourselves. That was one of the fields that really interests me. At that time, there wasn't a lot of mix pasteurizers. I think Ben & Jerry's had, probably, two people, and that was in the Waterbury plant.

It was fun. It was exciting. It was very busy. You used your mind and your body a lot. You learn what the mix is made of. You learn the ingredients you put in. You learned when it ran through the pasteurizer and the homogenizer, what the chemical and physical makeup of it actually did. That was exciting. It's kind of like how cheese is made. It's hard to explain, without going into scientific stuff.

Lam: What would you say is the hardest thing about your job now? And the most rewarding?

Sherwood: The hardest thing is probably because I've been here so long—how do I say this?—trying to relate to the younger kids as they come in, as high-school kids, just graduating. Trying to relate to them, and their work ethic, as compared to being a senior employee. Those are kids, and I used to look at myself, as the kid. Now, I'm not always the kid anymore. I'm supposed to be the grown up and that's kind of hard for me, I like being the kid. That's hard.

The easiest part is that I have met so many amazing people working here. Even still, to this day, I meet amazing people. There are so many people here that have my back, and I have their back on a daily basis. You've just got to work with them to understand that. It's kind of that corny thing where they say, “there's a family here.” It's more than that. I don't even have the words for it. You're here, you live with them everyday. You live with them more than you live with your family sometimes. They're just great people. There's so many different personalities, we fight like brother and sister and we get along like brother and sister. That's the best part of it.

Lam: Do people in your life, outside of work, ever ask you for ice cream?

Sherwood: Oh my God, absolutely. They think I'm a rock star because I know Ben [Cohen] and Jerry [Greenfield]. It's crazy. I've known Ben and Jerry for most of my life. They're awesome people. To me, I don't think they're rock stars, I think they're the average person. To people outside of Ben & Jerry's, they are rock stars. It's cool.

Lam: Do you oblige when people ask you for ice cream?

Sherwood: I share my wealth.