Common External Bread Faults: Identifying and Addressing Issues

Every baker – whether a student perfecting their craft or a seasoned professional – has pulled a loaf out of the oven only to find something off: the top has blown apart, the crust is too pale, the loaf looks lopsided, or odd blisters have formed on the surface. These are external bread faults, and they are more common than you might think. The good news is that most of them are entirely preventable once you understand what causes them. A good loaf of bread is judged by its volume, bloom, shape, colour, texture, sheen, moistness, and flavour – and all of these qualities start on the outside. Let’s go through the most common external faults, what causes each one, and how to fix them.

What are external bread faults? 🔗

External bread faults are defects that affect the visible, outer qualities of a loaf – its volume, crust colour, surface texture, and overall shape. These faults can stem from improper yeast levels, under or over fermentation, or incorrect oven temperatures. What makes them particularly tricky is that they are often the result of multiple small errors interacting together rather than one single mistake. A dough that was slightly too warm, combined with a fraction too much yeast and a slightly overextended proof time, can produce a loaf that looks nothing like what was intended. Process control – at every stage from mixing to baking – is what separates consistent results from unpredictable ones.

Excessive loaf volume 🔗

An oversized loaf that pushes out of its pan or domes dramatically is usually the result of too much gas production in the dough before it hits the oven. The three main culprits are overproofing, too much yeast, and dough that is too warm.

Causes 🔗

Overproofing is the most frequent cause. Overproofing results in loaves with pale crust colour, coarse grain, poor texture, and a flavour with acid overtones. The dough has simply been allowed to ferment beyond its optimal point, exhausting the gluten structure and producing more gas than the dough can hold. Too much yeast speeds up the entire fermentation process, causing rapid and excessive expansion. High dough temperature accelerates yeast activity in the same way – warm dough ferments faster, and if this isn’t accounted for in the proofing time, the result is a loaf that over-expands.

Solutions 🔗

Monitor the dough carefully during proofing – it should roughly double in size, not more. Once the dough has doubled in size, yeast has reached its maximum capacity; any additional rise beyond that point is carbon dioxide being released into the dough, which weakens the structure. Use the exact yeast quantity specified in your recipe, and control dough temperature by using cooler water during mixing or adjusting the room temperature in your proofing area.

Lack of volume 🔗

On the opposite end of the scale, a loaf that fails to rise adequately produces dense, heavy bread with a tight crumb. This is just as problematic as excessive volume and often disappoints both in appearance and eating quality.

Causes 🔗

Underproofing – not giving the dough enough time to ferment – is the primary cause. Underproofing yields small loaf volume, shell tops, inadequate flow, and bursting at the sides. Insufficient yeast slows fermentation, reducing the amount of carbon dioxide trapped in the gluten network. Cold dough temperature has the same inhibiting effect – yeast activity drops significantly in cooler conditions, and the dough simply doesn’t develop enough gas to produce adequate lift.

Solutions 🔗

Allow the dough to proof fully before baking. A simple poke test helps: gently press the dough with a fingertip – if it springs back slowly, it’s ready. If it springs back immediately, it needs more time. Use the correct amount of fresh yeast (always check expiry dates), and ensure your water is warm enough during mixing. Water should be between 105°F and 115°F when proofing yeast, and room temperature during rising should ideally be between 75°F and 85°F.

Pale crust 🔗

A pale, washed-out crust is more than an aesthetic problem – it usually signals that the bread is underbaked, and it can also indicate that the Maillard reaction (the browning process responsible for crust flavour and colour) hasn’t occurred properly.

Causes 🔗

A low baking temperature is the most direct cause – insufficient oven heat prevents the crust from browning. Insufficient baking time has the same effect. Underproofing can also contribute, as an underproofed dough doesn’t have adequate residual sugars available for browning. Similarly, insufficient sugar or milk in the recipe reduces the availability of fermentable sugars that caramelise and produce colour during baking.

Solutions 🔗

Verify your oven temperature with an oven thermometer – most ovens run slightly hotter or cooler than their dial indicates. Extend baking time until the crust achieves a deep golden-brown colour. Including a small amount of sugar in the dough can enhance browning, as sugars caramelise under heat and contribute to crust colour and flavour.

Overly dark or burnt crust 🔗

An excessively dark crust – or one that is partially burnt – negatively affects both flavour and texture. The outer layer becomes bitter and hard, masking the natural flavour of the bread.

Causes 🔗

Too high a baking temperature causes the surface to darken before the interior is fully baked. Excessive baking time produces a similar effect. Too much sugar in the dough accelerates caramelisation and can cause the crust to darken far faster than expected, particularly in enriched doughs. Overproofing is also a less obvious contributor – excess yeast activity can increase residual sugar content in ways that speed up browning.

Solutions 🔗

Lower the oven temperature slightly and monitor the bread closely as it bakes. Remove the loaf from the oven when the crust is a rich golden-brown. If the crust is browning too quickly before the interior is set, loosely tent the loaf with foil to slow surface darkening while the centre finishes baking. Stick closely to the recipe’s recommended sugar quantities.

Crust blisters 🔗

Blisters on the crust surface – small or large bubbles that give the loaf an uneven, bumpy appearance – can arise from several distinct causes. Blisters on bread crusts are primarily caused by overproofing, high oven humidity, or excessive hydration in the dough, as these conditions create air pockets that expand and burst during baking.

Causes 🔗

According to experienced bakers, air pockets that cause blisters on pan breads can result from over-mixed dough, too slack a dough, improper moulding, too much steam in the proof box, rough handling before baking, or too much top heat in the oven. High proofing humidity is a particular concern: if humidity is too high during proofing, moisture condensation can form on the dough’s surface, resulting in a tough crust and surface blisters in the finished bread.

Solutions 🔗

Maintain proofing humidity at a controlled level – a relative humidity of 85-95% is recommended during final proofing. Avoid excess steam in the oven, handle the dough gently during shaping and loading, and ensure the dough isn’t over-fermented before it enters the oven. Slack dough (dough that is too wet or under-developed) should be addressed by reviewing water ratios and mixing times.

Wild break or flying tops (shell tops) 🔗

This fault occurs when the top crust of the loaf doesn’t rise gradually and evenly, but instead bursts or splits open in an uncontrolled way – creating a jagged, cracked, or lifted top that is sometimes called a “flying top” or “shell top.”

Causes 🔗

If the gluten is not adequately conditioned during fermentation, the top crust – instead of rising gradually – will burst open under the pressure of expanding gas. This is typically linked to underfermented dough where the gluten structure hasn’t relaxed sufficiently to accommodate expansion. A very hot oven can also cause premature crust setting – the surface crust firms up too quickly, trapping expanding gas underneath, which then forces its way out.

Solutions 🔗

Ensure the dough is adequately fermented and relaxed before shaping and baking. Scoring the surface of the loaf with a sharp blade before baking is one of the most effective preventive measures – it creates a deliberate weak point that allows gas to escape in a controlled direction rather than bursting unpredictably. Also confirm that oven temperature is not excessive for the dough type being baked.

Blind appearance (no break or shred) 🔗

In contrast to flying tops, a “blind” loaf has no break or shred at all – the crust remains entirely smooth and tight, with no evidence of oven spring or expansion.

Causes 🔗

If the dough is over-fermented, the gluten loses its resistance, and no break or shreds are produced – this is known as a blind appearance. Other contributing factors include underfermented dough, overproofing, high oven temperature, and slack dough.

Solutions 🔗

Correct fermentation time is essential. Both over- and under-fermented doughs can produce a blind loaf, so precise process control and timing matter significantly. Dough consistency – not too stiff, not too slack – also plays a role. If the oven is running too hot, the crust sets before any meaningful expansion can take place.

Uneven or irregular shape 🔗

A misshapen loaf – one that is lopsided, bulging on one side, or asymmetrical – is often the result of errors during moulding and shaping, though fermentation and oven conditions can also contribute.

Causes 🔗

Uneven moulding pressure during hand-shaping is a common cause. While moulding bread by hand, even pressure should be applied so that the moulded piece of dough has an even appearance. Uneven oven temperature (hot spots in the oven) can cause one side of the loaf to rise and set faster than the other. Placing loaves too close together in the oven can restrict rise on adjacent sides. Pans that are too large or too small for the dough weight also produce misshapen loaves.

Solutions 🔗

Apply consistent, even pressure when shaping dough and ensure all pieces are uniform in weight if baking multiple loaves. Preheat the oven thoroughly and make sure the oven rack is level to promote even heat distribution. Rotate the loaf halfway through baking if your oven has known hot spots. Use the appropriate pan size for your dough weight – a general rule is that the dough should fill roughly two-thirds of the pan before proofing.

The role of process control in preventing external faults 🔗

Looking at all the faults above, a clear pattern emerges: the vast majority of external bread faults are rooted in imbalances during fermentation, proofing, or baking. Overmixing weakens the dough while undermixing underdevelops it – each causes poor gas retention, which ultimately manifests as a visible fault on the outside of the loaf. Similarly, in a proofing environment, relative humidity levels of at least 80% are needed to prevent skins from forming on the dough during final proofing, while excessive humidity creates the blistering and condensation issues discussed earlier.

The key variables to monitor at every bake are: yeast quantity and freshness, dough temperature, fermentation and proofing time, proofing humidity, oven temperature accuracy, and handling technique. Small, incremental adjustments to these variables – rather than dramatic changes – are the most effective way to diagnose and eliminate external faults over time. Keeping a baking log where you note dough temperature, proofing duration, and oven settings for each batch makes it far easier to trace the source of a fault when it appears.

External faults are not signs of failure – they are diagnostic clues. Each imperfect loaf tells you something specific about where the process went off track. With the understanding of causes and corrections outlined above, you have the tools to read those clues and respond with a targeted adjustment rather than guesswork.

What do you think? Of all the external faults covered here, which one do you find most difficult to diagnose in practice – and do you think most bakers focus enough attention on proofing conditions like humidity and temperature, or do they tend to look for the fault only at the oven stage?

References

1. https://doughhowblog.com/2012/10/24/bread-faults-and-their-causes/
2. https://www.slideshare.net/rohitmohan754/bread-faults
3. https://bakerpedia.com/processes/final-proof/
4. https://dontwastethecrumbs.com/ultimate-troubleshooting-guide-for-baking-bread/
5. https://redstaryeast.com/tips-troubleshooting-guide/
6. https://voyoeats.com/how-to-prevent-undesired-blisters-on-baguette-crusts/
7. https://www.thefreshloaf.com/node/24456/horrid-blisters-crust
8. https://www.yizeliadditive.com/info/common-problems-in-bread-making-yizeliadditive-102837937.html
9. https://bakerytechlimited.com/bread-troubleshooting
10. https://www.polygongroup.com/en-US/blog/the-importance-of-humidity-control-in-bakeries/