Good-quality borosilicate glass containers, including ours, are freezer-safe and very unlikely to crack from the cold on its own. Almost every crack happens for one of two avoidable reasons: not enough headspace for liquid to expand as it freezes, or a sudden jump in temperature at one end of the freezing or thawing process. Leave roughly 2.5cm of space above soup, stew or sauce, let hot food cool to room temperature before it goes in, and a borosilicate glass container should handle years of freezer use without issue.
Why do some glass containers crack in the freezer?
Glass containers crack in the freezer because of thermal shock or trapped pressure, not because they are cold. Thermal shock happens when one part of the glass heats or cools faster than the rest, so the two areas expand or contract at different rates until the glass gives way — which is why going straight from a hot oven into cold water cracks a dish, and why a container that's already under strain from being overfilled is more likely to fail. Liam Spencer of Northallerton Glass puts it simply: "you should only place a glass container in the freezer if it is labelled as freezer-safe," and explains that borosilicate glass, the type used in ovenware like Pyrex and in our containers, handles this far better than thinner or decorative glass because it has no air pockets that contract unevenly as the temperature drops. (Source: Ideal Home, "Can you put glass in the freezer?") Cheap, thin glassware is the kind that tends to crack; a borosilicate base built for oven, freezer and microwave use is a different material entirely.
How much space should you leave for soup, stews or sauces?
Leave about an inch — roughly 2.5cm — of space at the top of the container before you freeze any liquid, because water-based food expands as it turns to ice and a container filled to the rim has nowhere for that expansion to go. Sarah Heaps of AO.com advises exactly this, and also recommends not overfilling the freezer itself, since pressure from other items pressing against a full container can contribute to cracking too. (Source: Ideal Home) In practice, that means a 1040ml container is safer for a litre of soup than filling it to the very top, and it's one more reason smaller, separate portions tend to be more forgiving than one large batch crammed into a single tub. Our 10-piece glass meal prep set mixes 1040ml containers for mains with 370ml containers for sauces or sides, which gives you room to leave that headspace without needing to guess sizes.
Do you need to cool food before it goes in the freezer?
Yes — UK government food safety guidance says to cool cooked food and get it into the fridge or freezer within one to two hours, rather than putting a steaming-hot pan straight into the freezer. (Source: gov.uk, "How to chill, freeze and defrost food safely") This matters for two reasons at once: food that takes too long to cool sits in the temperature range where bacteria multiply fastest, and glass that goes from hot straight to a freezer's cold air is exactly the kind of rapid temperature swing that causes thermal shock. Splitting a big batch of chilli or bolognese into several smaller containers rather than one large one helps it cool faster on the counter, which gets it safely into the freezer sooner and is gentler on the glass at the same time.
How long can batch-cooked food actually stay in the freezer?
A freezer running at around -18°C keeps food safe to eat for a long time, but quality is what actually declines — government guidance puts cooked meat dishes at their best within two to three months, and baked goods, fruit and vegetables within three to four months. (Source: gov.uk) Writing the date on a label, or on a strip of tape on the lid, is the easiest way to actually use that guidance rather than guessing when a tub went in. It's also worth knowing that cooked food can be frozen again after defrosting, but the FSA's advice is that it should only be reheated once after that — so freeze in portions sized for one meal rather than one big block you'll need to reheat twice to get through.
Is it better to freeze one big batch or several smaller portions?
Smaller portions are almost always the better choice for home freezing: they cool faster on the counter, freeze through more evenly, and let you defrost exactly what you need instead of thawing an entire week's batch cook for one dinner. A 370ml container suits a single side, a child's portion or a sauce for one meal, while an 850ml or 1040ml container is sized for one adult main. Our 6-pack of 370ml kids' containers and the 370ml containers in the 10-piece set both work well for this kind of portioning, whether you're freezing school dinners for the week ahead or just not fancying bolognese four nights running.
Which Good For You glass containers suit batch freezing?
If you're freezing a mix of mains and sides, the 10-piece set (five 1040ml containers plus five 370ml containers) covers both in one go. If every portion is roughly the same size, the 5-pack of 850ml containers keeps things simple for a week of identical dinners. For a little one's portions, the 6-pack of 370ml kids' containers is sized for school-age meals rather than adult ones. Every set is LFGB-certified, BPA-free borosilicate glass, and carries a 2-year warranty — so if a silicone seal eventually wears out after a couple of years of freezer use, you can replace that one part rather than binning glass that's otherwise perfectly fine. If you're scaling a family recipe up for a bigger freezer batch, a set of copper measuring cups and spoons makes it easier to keep ratios right when you're doubling or tripling the ingredients.
Frequently Asked Questions
Will my glass meal prep containers crack in the freezer?
Not from the cold alone — borosilicate glass containers like ours are designed to go in the freezer safely. Cracks almost always come from overfilling a container with liquid that then expands, or from a sudden jump in temperature, such as putting steaming-hot food straight in or moving frozen glass straight into a very hot oven.
How much space do I need to leave when freezing soup or stew in a glass container?
Leave about 2.5cm (roughly an inch) of space at the top of the container, because liquid expands as it freezes and a container filled to the rim can crack under that pressure. This matters most for watery dishes like soup, stock or stew, which expand more noticeably than thicker dishes like a bolognese or curry.
Can I put hot food straight into the freezer in a glass container?
It's better not to — let food cool to room temperature first, and ideally get it into the fridge or freezer within one to two hours of cooking, as UK government food safety guidance recommends. This both avoids the rapid temperature swing that can stress the glass and keeps the food out of the temperature range where bacteria multiply fastest.
Is all glass freezer-safe, or only certain types?
Only glass labelled as freezer-safe should go in the freezer. Borosilicate glass, the type used in ovenware and in our containers, handles freezing and thermal shock far better than thinner or decorative glass, because it doesn't have the air pockets that cause uneven glass to contract and crack as it cools.
How long can I keep batch-cooked food in the freezer before quality drops?
A freezer kept at around -18°C keeps food safe for a long time, but quality is what actually fades — UK government guidance puts cooked meat dishes at their best within two to three months, and baked goods, fruit and vegetables within three to four months. Labelling containers with the date you froze them is the simplest way to keep track.
Should I freeze one big batch or lots of small portions?
Small portions are usually better: they cool faster before freezing, freeze through more evenly, and let you defrost exactly what you need rather than thawing an entire batch for a single meal. A 370ml container suits a single portion or side, while an 850ml or 1040ml container suits one adult main.