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How to Smooth Sugarpaste for a Professional Finish
By Kay Bourke, Founder of Beau Products
Kay has been handmaking sugarpaste in Long Crendon, Buckinghamshire since 2005. Beau Products is a certified nut-free artisan producer and Great Taste Award winner, trusted by home bakers and professionals across the UK for over 20 years.
Smoothing sugarpaste
Smoothing sugarpaste is the process of eliminating imperfections — air bubbles, fingerprints, fold marks, uneven surfaces, and rough textures — from a cake covered in sugarpaste, to achieve the clean, polished finish associated with professional cake decoration. The process uses specialist flat tools called cake smoothers, combined with specific techniques, temperature management, and a final buffing step. A well-smoothed cake has a surface with no visible joins, no texture variation, and edges that are either cleanly rounded or sharply defined, depending on the chosen finish.
New to sugarpaste? This guide focuses on the smoothing stage. If you haven't covered your cake yet, start with our step-by-step guide: How to Cover a Cake with Sugarpaste.
The single thing that separates a home-made-looking cake from a professional-looking cake is most often not the decoration — it's the surface beneath it. A beautifully piped border around a lumpy, fingerprinted sugarpaste finish still looks amateurish. A simple ribbon around a flawlessly smooth, sharp-edged cake looks expensive and deliberate.
Smoothing is the most underinvested step in cake decoration. Most bakers spend a lot of time on the covering and the decoration and not enough on the 10 minutes in between that determines the quality of everything else. This guide covers exactly those 10 minutes — and the decisions around them that make the difference between a good cake and a great one.
Tools for Smoothing Sugarpaste
You cannot achieve a professional finish with your hands alone. The tools below are what make the difference — and none of them is expensive.
Essential
- Flat cake smoothers (a pair) — the primary smoothing tool. Flat plastic or acrylic paddles that are pressed firmly against the paste surface and moved in circular or sweeping motions. Having two allows simultaneous pressure on top and side to create a sharp top edge — one of the defining techniques of a professional finish. A pair costs £6–12 and lasts indefinitely. This is the most important tool purchase for anyone serious about sugarpaste work.
- Cake scraper or side scraper — a long, flat-edged tool held against the side of the cake and drawn around as the turntable rotates, creating a perfectly even, flat side surface. Used in conjunction with a smoother for the most precise side finish.
- Rotating turntable — not strictly a smoothing tool, but working on a turntable transforms the smoothing process. Being able to rotate the cake steadily while holding the smoother still in position is far more controllable than rotating the smoother around a stationary cake.
- Cornflour in a small muslin bag or fine sieve — for very light dusting to reduce stickiness on the paste surface during the final buffing step.
Helpful but not essential
- Flexi-scraper or Garrett frill cutter — a thin flexible tool useful for getting into the base edge of the cake where a rigid smoother cannot reach cleanly.
- Foam pad or piece of foam sponge — used in the final buffing step to bring a subtle sheen to the paste surface.
- Pin or scriber tool — for releasing trapped air bubbles beneath the paste without leaving a visible mark.
- Spirit level or cake decorating ruler — for checking that the top of the cake is perfectly flat before smoothing begins. A cake that is not level before covering cannot be levelled by smoothing.
Kay's tip: If you can only buy one thing to improve your sugarpaste finish immediately, buy a second smoother. The single-smoother technique is a ceiling — it can only take you so far. Two smoothers, held simultaneously on top and side of the cake and pressed together at the edge, is how the clean right-angle finish that defines modern professional cakes is achieved. It is genuinely not possible to replicate that edge with one smoother alone.
The Foundation That Makes Everything Possible
Every professional cake decorator knows this truth: no amount of smoothing technique can compensate for a poor base coat. The surface beneath the sugarpaste is what the paste conforms to, and any bump, ridge, or indentation in the ganache or buttercream will be visible through the paste once it is applied — regardless of how long you spend with a smoother.
Before the sugarpaste goes on, your base coat needs to pass three tests:
- Smooth — run your hand over it. You should feel no lumps, crumbs, or ridges. If you can feel a bump, the paste will show it.
- Set firm — the base coat must be fully chilled and set before covering. Soft buttercream will move under the paste as you smooth, creating ripples. Ganache should be completely firm. Buttercream should be chilled until it doesn't indent when pressed lightly.
- Level — the top must be flat. Use a spirit level, a flat ruler, or simply sight the cake at eye level. A cake that is not level before covering will not be level after — and a crooked sugarpaste finish is the thing an eye goes to first.
Kay's tip: Ganache is a better base coat than buttercream for achieving a truly flat, smooth sugarpaste finish. It sets harder, levels more reliably, and gives the smoother a firmer surface to work against. If you regularly struggle to get a flat result with buttercream underneath, try a white chocolate ganache base — it is not as sweet as you might think, and the improvement in your surface finish will be immediately visible.
How to Smooth Sugarpaste: Step by Step
These steps begin at the point where the sugarpaste has just been draped and is lying in place on the cake — sides not yet smoothed down, excess not yet trimmed. If you haven't covered the cake yet, complete the covering process first, then return here for the smoothing technique.
Step 1
Smooth the top surface first — before touching the sides
With the paste draped over the cake, place your smoother flat on the top of the cake and use firm, circular motions to work out from the centre. You are pressing out any air and ensuring the paste is making full, even contact with the base coat beneath.
Work systematically from the centre to the edges. If you spot an air bubble rising under the paste, press it outward toward the nearest edge now — it is much harder to deal with once the sides are smoothed down. Do not press the top edge down yet; that happens in Step 4.
The top is finished for now when there are no visible bubbles, no areas of paste that are not fully in contact with the cake, and the surface feels firm and even under the smoother.
Step 2
Work down the sides — coaxing, not pulling
Use your hands — not the smoother yet — to ease the excess paste away from the sides of the cake. The technique is a gentle lifting and outward motion: lift the paste hanging below the base of the cake outward and away, then smooth it upward against the side of the cake. Never pull the paste downward — this creates the stretched, textured appearance known as elephant skin that cannot be undone.
Once the paste is lying flat against the sides with no deep folds, take a smoother and use long, sweeping upward strokes to firm the paste against the side. Work around the cake in sections, pressing firmly and confidently. Light, tentative strokes leave marks — firm, purposeful strokes create a smooth surface.
Step 3
Trim the base and press the edge flat
Hold a sharp knife flat against the cake board and run it around the base to trim the excess paste cleanly. Keep the blade truly flat — angling it even slightly will either leave a visible gap at the base or cut into the bottom edge of the paste.
Once trimmed, use your smoother to press the base edge down firmly against the board, working around the full circumference. This creates a clean, defined base line — the difference between a cake that looks like it's sitting properly on its board and one that looks slightly unfinished.
Step 4
Create the top edge — choose your finish style
This is where you choose the finished look of your cake's top edge. There are two main styles — sharp and rounded — and the technique is different for each.
For a sharp, modern edge (the professional standard for contemporary cakes): Hold one smoother flat on top of the cake and a second smoother vertically against the side, pressed together at the top edge. Apply firm inward pressure from both smoothers simultaneously and work around the cake. The corner of paste between the two smoothers is compressed and defined into a clean right angle. This is the technique that produces the sharp-edged look you see on professional patisserie and competition cakes.
For a soft, rounded edge (traditional and forgiving): Use a single smoother held at a 45-degree angle to the top edge and move it around the cake with gentle pressure. The edge rounds naturally and softly without the sharp definition of the two-smoother method. This style suits vintage, floral, and more traditional cake designs.
Kay's tip: The two-smoother sharp edge technique feels counterintuitive the first time. Most people expect to need to press very hard. In practice, the pressure needed is moderate and consistent — it's the evenness of the pressure across the whole edge that creates the definition, not force. If you press too hard in one spot, you'll leave an indentation. Go around the cake twice with medium pressure rather than once with heavy pressure.
Step 5
Use a scraper for a perfectly flat side surface
For the most perfectly flat side surface, use a cake scraper (or the flat edge of a long ruler) in addition to your smoother. Hold the scraper vertically against the side of the cake with its bottom edge resting on the board, and rotate the turntable steadily while holding the scraper still. The scraper shaves off any high points and creates a geometrically flat surface that smoothers alone cannot always achieve.
This technique is more common on ganache-based cakes but works on sugarpaste too — particularly useful when working on a square cake where flat sides are visually critical.
Step 6
Handle square cake corners correctly
Square cakes present a specific challenge that round cakes don't: the corners. Extra paste naturally accumulates at each corner during draping and if not managed correctly creates a thick, folded edge that smoothers cannot flatten.
For each corner: before smoothing the sides, use your fingers to gently ease the paste at the corner outward — there will be a natural fold of excess paste here. Work from the top of the corner downward, easing the fold out into a smooth, vertical edge rather than pressing it flat. If a small pleat forms at the base of the corner, carefully cut it away with a small pair of scissors and smooth the cut edge together — a small, neat join at the base of a corner is far less visible than a thick fold running the full height of it.
Step 7
Do a full inspection pass and fix any remaining issues
Before the paste begins to crust over (typically 15–30 minutes after covering, depending on the room temperature), do one careful visual inspection of the entire cake. Look for — and address — the following:
- Air bubbles: pierce at a very shallow angle with a clean pin, press flat, smooth over. The hole closes almost invisibly.
- Fingerprints or tool marks: hold a dry smoother firmly on the mark and move it with firm circular pressure. Recent marks warm and press out; marks that have already crusted may need the warm-hand technique in Step 8.
- Small cracks: if the paste is still fresh, smooth firmly over the crack with a fingertip dampened with the tiniest amount of water. For a slightly drier paste, a small amount of vegetable shortening on the fingertip works better. Do not over-wet.
- Uneven sides: use the smoother with firm, long vertical strokes on any area that appears thicker or less flat than the rest.
Step 8
The final buff — the step most bakers don't know about
Once you are satisfied with the smoothness and edges, leave the cake for 20–30 minutes to allow a light crust to form on the paste surface. Then — and this is the step that separates the very best finishes from the merely good — use a small piece of foam (the type sold for floral arrangements or available cheaply from a craft shop) to lightly buff the surface of the paste.
Hold the foam lightly and use quick, circular buffing motions over the entire surface of the cake — top and sides. The foam smooths out the very finest surface texture variation and brings a soft, even sheen to the paste. If the surface feels slightly sticky, very lightly dust with cornflour through a fine sieve first, then buff.
This is the step that makes a sugarpaste surface look like it has been lacquered. It takes two minutes and makes an immediate, visible difference.
Kay's tip: The foam buffing step was shown to me by a competition judge years ago and I have used it on every cake since. The difference is subtle in photographs but very visible in person — and on a wedding cake or a competition piece, in-person is all that matters. Invest in a small block of foam (literally pennies) and keep it in your kit. Once you've used it, you will never cover a cake without it.
Sharp Edge vs Rounded Edge: Which Finish and When
The top edge of a sugarpaste-covered cake is one of the most visible design decisions in cake decoration — and a deliberate choice rather than a default. Here is when each style is most appropriate.
| Sharp edge | Rounded edge | |
|---|---|---|
| Look | Modern, architectural, precise | Soft, traditional, approachable |
| Best for | Contemporary wedding cakes, competition cakes, geometric designs, minimalist styles | Vintage designs, floral cakes, children's cakes, ruffle and lace work |
| Technique | Two smoothers simultaneously, one on top and one on side, pressed together | Single smoother at 45° angle to the top edge |
| Difficulty | Intermediate — requires consistent simultaneous pressure | Beginner — more forgiving of inconsistency |
| Base coat | Ganache strongly recommended — gives sharper result | Ganache or buttercream — both work well |
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Common Smoothing Problems and How to Fix Them
| Problem | Cause | Fix |
|---|---|---|
| Elephant skin (wrinkled texture on sides) | Paste was pulled downward rather than coaxed outward and downward during covering | Cannot be smoothed out once set. If caught immediately, re-lift the paste carefully and re-drape. Prevent next time by never pulling downward. |
| Smoother leaving drag marks | Smoother too cold, or paste too sticky (too humid or too warm) | Very lightly dust surface with cornflour before smoothing. Ensure the smoother surface is clean and slightly warm from your hand. |
| Top edge collapsing inward | Paste too warm and soft; two-smoother pressure applied before paste has firmed slightly | Leave the covered cake for 10–15 minutes before attempting edge sharpening. Work in a cooler room. Apply lighter pressure in more passes. |
| Visible bump under the paste | Uneven base coat; crumbs or debris in the base coat | Cannot be removed through smoothing. Re-cover with a better base coat. Accept small bumps as part of a learning process. |
| Fingerprints on a hardened surface | Handling the cake with bare hands after the paste has crusted | Press a smoother firmly over the mark with circular pressure — light heat from the friction helps. Or use the foam buffing technique on the whole surface. Always handle set cakes by the board, not the paste. |
| Side surface not perfectly flat — wavy appearance | Uneven paste thickness; smoother not held firmly enough against side | Use a long, straight scraper held against the side while rotating the turntable. Work around the cake multiple times. Ensure you are rolling to an even thickness when covering next time. |
| Square corner tear or crack | Paste forced around corner rather than guided; paste rolled too thin at corner | Small tear: press edges together with a dampened fingertip and smooth firmly over. Large tear: re-cover the affected area with a patch cut from excess paste, sealed and smoothed. Position a decoration over the join. |
Frequently Asked Questions
Why does my sugarpaste have a rough, textured surface even after smoothing?
A rough or pitted surface almost always results from one of three causes: the paste was kneaded too little before rolling (leaving internal air that rises to the surface as texture); too much icing sugar was used when rolling (which dries the outer surface of the paste, creating a texture that smoothers then press in rather than eliminate); or the paste was old and had dried out in the packaging. The fix for all three is a fresher, better-kneaded paste and a very light dusting of icing sugar when rolling rather than a heavy coating.
How do I get a perfectly flat top on a sugarpaste cake?
A perfectly flat top on a covered cake begins with a level cake before covering — no smoothing technique can level a cake that is physically uneven underneath. Trim the baked sponge layers to be level before stacking and filling. Apply the base coat with a flat palette knife, using a spirit level or cake rule to check flatness before it sets. Once covered, use a flat smoother in firm circular motions from the centre outward to maintain the level surface. Sight the cake at eye level from different angles to check for any high or low spots before the paste sets.
Can I use a warm smoother to get a better finish?
Yes — a slightly warm smoother slides more easily over the paste surface and helps smooth out minor marks and texture variation. The warmth comes naturally from holding the smoother in your hand before use — you do not need to heat it artificially. Some professional decorators briefly warm a metal scraper under warm water (drying thoroughly) for the same effect on the final passes. Be careful not to overheat: a too-warm smoother can cause the paste to stick or leave impression marks rather than smooth them out.
What causes elephant skin on sugarpaste and can it be fixed?
Elephant skin — the wrinkled, crumpled texture on the side of a covered cake — is caused by pulling the paste downward when covering the sides rather than lifting the excess outward and smoothing it down. The paste is stretched beyond its elasticity and the surface buckles. If caught within the first minute or two, carefully peel the paste away from the affected area and re-smooth using the correct lifting technique. Once the paste has set even slightly, elephant skin cannot be corrected through smoothing. It is purely a prevention problem, not a fixing one.
How long should I wait before adding decorations to a smoothed cake?
Allow the covered and smoothed cake to rest for at least 30–60 minutes before applying decorations that require pressure against the surface (such as pressed sugar flowers, embossed patterns, or painted designs). The paste needs time to form a light crust that will not be disturbed by the pressure of decoration application. For heavy decorations or those requiring edible glue, waiting 2–3 hours gives a firmer surface to work against and reduces the risk of the decoration weight causing the paste to indent.
Is there a trick to getting a shiny sugarpaste finish?
A high sheen on sugarpaste is achieved through the foam buffing technique described in Step 8 above. Once the paste has crusted slightly (20–30 minutes after covering), buff the entire surface with a small piece of foam using quick circular motions. A very light dusting of cornflour beforehand helps if the surface is at all sticky. The result is a soft, even lustre rather than a high gloss — sugarpaste cannot achieve the mirror finish of a poured glaze, but the buffed finish is the closest it can get and is widely regarded as the correct finish for a professional covered cake.
Practice Makes the Difference
Smoothing technique is purely a matter of practice. The movements involved — the circular pressure of the smoother, the simultaneous two-smoother edge technique, the final foam buff — become muscle memory after a handful of cakes. The bakers who get a professional finish are not doing anything magical; they are doing the same steps, with the same tools, repeatedly until the result is consistent.
The most important investment you can make is buying a second smoother and starting to use the two-smoother edge technique on your next cake, even if it feels awkward the first time. The difference in the finished edge is immediately visible — and once you've seen it, it is very difficult to go back to a rounded edge on anything you want to look truly professional.
Any questions about smoothing technique, paste consistency, or getting the right result for a specific occasion — email us at hello@beauproducts.co.uk or call 01844 202166. We're here Monday to Friday, 9am–3pm, and we love talking about this.
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Ready to cover your next cake?
Browse Beau's 50+ handmade sugarpaste colours — from crisp White and classic Ivory to deep Navy and rich Burgundy. Fresh to order from our certified nut-free facility in Buckinghamshire, in sizes from 100g tasters to 10kg professional packs.
→ Shop all sugarpaste colours at beauproducts.co.uk/collections/sugarpastes
Haven't covered the cake yet? Read this first: How to Cover a Cake with Sugarpaste — Step by Step
Published by Beau Products · beauproducts.co.uk · The Sweet Edit by Beau