No. It is the reason the ingredient list is short. The can is filled, sealed, and then warmed through for about 45 minutes, which does the job of a preservative.
Tunnel pasteurization is heat applied to a drink after it has already been sealed inside its can. The sealed cans travel slowly through a long-enclosed tunnel while warm water sprays over them, the liquid inside comes up to temperature and holds there, then cooler sprays bring it back down. We call it tunnel pasteurization. It is the reason a drink can sit on a warm shelf for months with nothing added to keep it there.
You will not find the word on a Luba. Most drinks are not required to declare it and most brands that do it never mention it, so the absence of the word from any can tells you nothing at all. We are telling you here instead.
It is worth knowing because this one step decides what else has to go in the can. A drink heated properly does not need a chemical preservative. A drink that is not heated almost always does. So when you are holding two cans and one ingredient list is twice the length of the other, this is usually why.
What we actually do to your can?
There is nothing exotic about it. Real fruit juice, cane sugar, a touch of monk fruit and reverse osmosis water, and a few other natural ingredients get blended together in a tank first, then that blend gets carbonated. Only after that does it go anywhere near a can.
The carbonated blend fills the cans, and the tops get sealed right there on the line. Then, and only then, the sealed cans ride a slow conveyor into a long-insulated tunnel, roughly the length of a school bus, while warm water rains down on them. The water comes up in stages rather than all at once, holds there a few minutes, then cools back down on the way out. About 45 minutes from one end to the other.
The can is never opened during any of this. Nothing is added to it once it is sealed. The only thing that reaches your drink from that point on is warmth coming through the wall of the can.
Why we wait until the can is shut?
Order is the whole technique, and it is the one piece of this worth understanding.
Blend, carbonate, fill, seal, then heat. Everything that keeps the drink stable happens after the can is already closed, which is why nothing has to go into the tank to do that job for us instead.
Flip that order and the risk shows up. Heat the liquid first and pour it into cans afterward, and everything downstream of that point has to stay clean: the filler, the seamer, the air in the room. Anything that gets in during filling is sealed in with the drink, with no second chance to deal with it. Sealing first removes that problem entirely. Whatever went into the can is handled inside it, and once it is shut nothing else can reach it.
We think of it less as a technical step and more as a choice. We are not accidentally a preservative-free drink. We are choosing a process over a chemical, and the tunnel is where that choice actually gets made.
Not all heat is the same
Retort, flash and tunnel all use heat, and they behave nothing like each other.
| Method | When the heat is applied | Typically used for |
|---|---|---|
| Tunnel pasteurization | After filling and sealing, through the container wall | Beer, cider, juice, ready-to-drink cocktails in cans and bottles |
| Flash pasteurization (HTST) | Before filling, in a plate heat exchanger, very hot and very brief | Milk, juice at scale, some draught beer |
| Retort | After sealing, but far hotter and under pressure | Low-acid canned foods: soups, beans, pet food |
Retort is the heavy one, hot enough to change flavor, which is why it is used for soup and not for something you drink cold. Flash heats the liquid before it goes into the can, which is quick but leaves the filling line to keep clean afterwards. Tunnel is the slow one, gentler than retort and sealed before it is heated, which is the part that matters.
Flash works well for something like milk, where a huge volume of liquid gets heated fast before it ever touches a container. For a canned drink built around real fruit juice, that faster, lighter heat treatment does not shut the door on yeast and bacteria the same way a full tunnel run does. That gap is part of why we run everything through the tunnel instead.
Does heat ruin the fruit?
Done badly or incorrectly, yes. Heat and fresh fruit are not natural allies, and an over-pasteurized drink tastes flat, slightly stewed, and a shade darker than it should be. Anyone who tells you heat has no effect at all is selling something.
Done properly the effect is small enough that trained judges do not flag it. Luba's Lime Margarita went through the tunnel like every other can and came out of the World Alcohol-Free Awards 2026 described by the judges as "all very natural tasting," with "lemon zest and pith." That is not the vocabulary of a cooked drink.
The honest reason we do it at all is not flattering. Put this much real fruit juice in a can, leave the preservative out, and the drink will eventually start to ferment in there. Something has to stop that happening. We would rather it were heat than a chemical.
Why almost nobody else bothers
None of the reasons is that it does not work.
A tunnel is slow, and it is a bottleneck on a line otherwise measured in cans per minute. It costs money as a machine, as floor space and as energy. And it is unnecessary if you are willing to add a preservative, which costs almost nothing and works.
That is the honest trade. A brand adding potassium sorbate to a tank is not doing anything wrong or unusual. They are making a different call about what the label should look like and what the drink should cost. How we know it worked
We do not take it on trust either. Every production run goes into microbiology testing before any of it is released, and the results take five to seven days to come back. If a run does not pass, it does not ship. That is the part nobody sees, and it is the part we would want to know about if we were the one buying it.
How we know it worked
We do not take it on trust either. Every production run goes into microbiology testing before any of it is released, and the results take five to seven days to come back. If a run does not pass, it does not ship. That is the part nobody sees, and it is the part we would want to know about if we were the one buying it.
The last thing that happens to a Luba
Luba is blended, carbonated and sealed into 12 oz cans at a partner cannery in Wisconsin, and every one of them goes through the tunnel before it is packed.
That is why the ingredient list reads the way it does. No preservative, because the heat already did that job. No dye, because the color comes from the fruit. If you take one thing from this page, take the short version: there is nothing in the can keeping it alive, and this is what we do instead.
FAQ
Does pasteurized mean cooked?
No. Cooking changes food and is meant to. This is a short controlled warming: the drink comes up to temperature, holds briefly, then comes straight back down. Nothing is added, nothing is boiled off, and the can is never opened.
Is pasteurized juice still real juice?
Yes. It is a temperature applied to the juice, not an ingredient added to it. Nothing goes in and nothing is taken out. Almost every juice sold outside a refrigerated case has been heated in some form.
Does the heat kill the nutrients?
Some heat-sensitive vitamins take a small hit, the same way they do in any pasteurized juice on any shelf. The trade is a drink you can keep in a cupboard for months with no preservative in it. If you are drinking a canned cocktail for the vitamin C, you were always going to be disappointed.
Do I need to refrigerate it?
No. That is the point of it. Keep it in a cupboard at room temperature and chill it whenever you want to drink it.
Why is it not written on the can?
Because it does not have to be. A drink like this is not required to declare pasteurization anywhere, and most brands that do it never mention it, so the absence of the word tells you nothing at all. The ingredient list is the better clue: a short list, no named preservative, sold off a warm shelf, usually means heat did the work.