Granite is quarried stone, and quarried stone absorbs liquid at a rate that varies from one granite to the next. That is why almost every instruction you will read on the subject is too general to be useful. Your worktop does not need sealing because a year has passed. It needs sealing when it starts absorbing, and there is a fifteen-minute test that tells you exactly when.
Key points
- The fifteen-minute water test tells you when to seal; a calendar does not
- Porosity varies by stone, so test near the sink and the hob rather than assuming
- A sealer is an impregnator that slows absorption, not a coating and not armour
- Buff off every trace of residue before it dries, or you will be removing haze instead
- Quartz and sintered stone never need any of this, which is a real ongoing advantage
The answer, before anything else
Put a tablespoon of water on the worktop, leave it a quarter of an hour, wipe it off and look at the stone underneath. If it has darkened, the granite is drinking and it is time to reseal. If it looks exactly as it did before, leave it and test again in a few months. That one check replaces every calendar rule and every "granite must be sealed annually" article you will find.
Do the test in more than one place. The stone near the sink and next to the hob works harder than the run behind the kettle and will usually fail first. It is perfectly normal for a worktop to want resealing around the sink and be fine everywhere else, in which case seal that area and leave the rest.
If you have quartz or a sintered surface such as Dekton, you can stop reading. Neither absorbs anything, neither can be sealed, and there is nothing here you need to do.
Why granite is sealed at all
Granite is porous, and how porous depends on the stone rather than on the word "granite". It is a natural rock with a crystalline structure, and the spaces between those crystals are what a liquid finds its way into. Dense, tightly grained black granites are close to unabsorbent in practice. Lighter, coarser, more open stones absorb far more readily, which is why a light granite behind a sink often wants attention while the rest of the kitchen does not.
That variability is the part the manufacturer pages skip, because they are describing a category rather than your slab. Porosity is a property of the stone; how fast the seal gets used up is a property of the household.
Every granite worktop we fabricate is sealed before it leaves us, and that seal is topped up over the life of the worktop rather than being permanent. If that sounds like more than you want to think about, it is a legitimate reason to look at engineered stone instead.
Why "seal it every year" is bad advice
The annual rule is repeated everywhere because it is easy to say, not because it is true. It depends on three things that vary independently: which granite you have, which sealer was used on it, and how the surface is treated. A calendar knows none of those. Follow it blindly and half of everybody seals stone that did not need it while the other half spends months with a worktop that is quietly absorbing.
Oversealing is not catastrophic, but it is not free either. A stone that cannot take any more will not absorb what you apply, so the excess sits on top and has to be buffed off completely. Do that carelessly and you get the hazy, patchy look people then blame on the sealer itself.
What a sealer actually is
A stone sealer is an impregnator, not a coating. It soaks into the pores near the surface and lines them, so liquid beads and sits long enough for you to notice and wipe away. It is not a film and not a varnish, and it does not sit on the stone as a layer you can see or feel. A product that claims to add gloss is a topical dressing rather than a sealer, and it will wear unevenly and need stripping.
That changes what to expect from it. A sealed worktop buys you time, not immunity. Red wine, olive oil, turmeric and beetroot will still stain sealed granite if left overnight; the seal means you have a window in which wiping up is enough. It reduces absorption. It does not make the stone bulletproof.
It also does nothing about etching. Etching is a chemical reaction between an acid and the minerals in the stone, and it damages the polish rather than staining the body of the material. Lemon juice, vinegar and descaler will dull a susceptible stone straight through a sealer, because the seal is inside the pores rather than over the polish.
How to seal a granite worktop
It is genuinely a job you can do yourself, and a normal kitchen is an evening at most. The step people get wrong is the last one.
Step by step
Step 1: Clear and clean the surface
Take everything off the worktop, including the things that live in the corner. Clean it with a pH-neutral stone cleaner or warm soapy water and lift off any dried-on residue. Anything left on the surface gets sealed under the product, so a mark ignored now is a mark locked in.
Step 2: Let it dry completely
This matters more than anything else on the list. An impregnator cannot get into pores already full of water, so a surface that looks dry but is not takes the sealer unevenly and leaves patchy protection. Give it longer than you think it needs, especially around the sink cut-out and any join.
Step 3: Apply evenly, a section at a time
Work in manageable areas rather than the whole kitchen at once, so no part sits too long. Apply with a clean cloth or applicator and cover the surface evenly, including the front edge and the exposed edges of the sink cut-out: the parts most likely to be missed and the parts nearest the water.
Step 4: Let it dwell for the time the product states
Dwell time is how long the sealer is given to soak in, and it is set by the product in your hand rather than by any general rule. Read the label and follow it. If the stone drinks it in and dries out during that window, the label will usually call for a second coat there.
Step 5: Buff off every trace of residue before it dries
This is the step that goes wrong. With a clean dry cloth, remove all the sealer that has not soaked in, while it is still wet. Left to dry, it leaves a haze or streaky film that is a genuine nuisance to shift, usually needing more product to redissolve it and a second go at buffing. Check the surface from a low angle in good light before you walk away.
Step 6: Leave it alone, then test it
Give the worktop the cure time the product asks for before it gets wet or takes weight, then repeat the water test where it failed. Beading rather than darkening means the job is done. Still darkening means that area wanted a second coat.
Two practical points. Open a window and ventilate properly: solvent-carried sealers give off fumes. And follow the instructions on the product you bought rather than a generic method from anywhere, this page included, because dwell times, coat counts and cure times differ between formulations.
What not to use on granite day to day
Most granite that ends up needing attention got there through cleaning products rather than cooking. Each item below is on the list for a reason rather than out of caution.
Keep these away from the worktop
- Acidic cleaners, and anything containing lemon, vinegar or citric acid: acid attacks the minerals in the stone and dulls the polish, and no sealer prevents it
- Limescale removers and descalers: acidic by design, which is exactly the problem. The ring round your tap comes off with warm soapy water and patience
- Bleach and bleach-heavy sprays left standing: a quick wipe and rinse is survivable, a puddle overnight can lighten the stone and will strip sealer
- Abrasive pads, wire wool and scouring cream on a polished finish: they take microscopic scratches out of the polish, which reads as a dull patch and cannot be sealed away
- General kitchen sprays as the everyday cleaner: most are mildly alkaline and flatten a polish over years rather than overnight
- Steam cleaners aimed at the surface, the joins or the silicone: heat and pressure drive water into the places you spent money keeping it out of
What to use instead is unglamorous: warm water, a soft cloth and a little washing-up liquid, dried off afterwards in a hard water area, plus a pH-neutral stone cleaner for a periodic proper clean. That is the entire regime.
What sealing will not fix
Sealing is preventative. It stops the next thing getting in and does nothing about what is already there, and applying it over damage usually makes that damage more permanent.
- An existing stain: sealing over it locks it in. Draw it out with a poultice first, then seal once the area is clean and dry
- Etching: the polish has been chemically damaged and needs repolishing, not sealing
- A chip or a crack: that is a repair, usually a colour-matched resin fill polished back, and no product in a bottle addresses it
- A dull patch from abrasion: scratched polish is a mechanical problem with a mechanical fix
- Limescale and hard water spotting: cosmetic, sitting on the surface, and nothing to do with the seal underneath
If a mark has already soaked in, our guide to removing stains from stone worktops covers the poultice method and which solvent suits which stain. Do that first, seal afterwards.
The comparison, fairly
Sealing is a real, ongoing difference between the three families, and one of the few maintenance differences that lasts as long as you own the kitchen.
| Granite | Quartz | Dekton and sintered | |
|---|---|---|---|
| Porosity | Porous, varies by stone | Non-porous | Effectively zero porosity |
| Sealing | Sealed on installation, topped up over time | Never needs sealing | Never needs sealing |
| Water test | Worth doing periodically | Pointless, it cannot absorb | Pointless, it cannot absorb |
| Etches from acids | Yes, on susceptible stones | Resin can be marked by strong chemicals | Highly resistant |
| Hot pan straight on it | Tolerant | No: use a trivet | Highly tolerant |
Read that table both ways. Quartz and sintered stone win outright on sealing, and if a periodic test and an occasional evening with a cloth irritates you, that is reason enough to choose one of them. But granite wins on heat, and the maintenance is a fifteen-minute test plus a short job on the occasions it fails. Neither answer is wrong, and our comparison of the three materials sets out the rest of the trade-offs.
When to call somebody instead
Do it yourself when the test fails and the surface is otherwise sound. Call somebody when anything else is going on, because sealing over a problem makes it harder to put right, not easier.
- The stone is stained, etched or has a dull patch, and needs sorting out before any sealer goes near it
- The whole worktop drinks water in seconds, which suggests it was never properly sealed
- A previous attempt has left a haze or a streaky film you cannot buff out
- A join has opened, a lip has appeared across it, or the silicone is lifting
- You are not sure what the stone is, or whether it is granite at all
If you are in any doubt, send a photograph to info@worktopworx.co.uk or ring +44 7830 847489 and describe what you are looking at. We will tell you whether it is a reseal, a repair or nothing at all, and we would far rather have that two-minute conversation than be asked to undo the wrong bottle. If the worktop turns out to be beyond saving, our worktop replacement service and the colour library are the next places to look.