King Alfred’s Cake

King Alfred's Cake

Walking through a woodland you will often see ash trees with black blobs on them, usually on dead branches or on branches that have fallen off the tree. This has several names including coal fungus or cramp balls or King Alfred's cakes.  These hard, semi-spherical black lumps are usually about 3-4 cm in diameter and are the fruiting bodies of a fungus, which decays the dead wood of the ash tree. The photo shows the inside of one of these pictured on a log in my back garden - not on an ash tree.

Legend has it that King Alfred, when in hiding from the Danes, once burnt some cakes by failing to take them out of the oven. These fungal growths, which look as if they have been burned, are a reminder of his poor cooking and hence are nicknamed “King Alfred’s Cakes”, but their correct Latin name is Daldinia concentrica. They grow in either a black form or a dark brown – perhaps the lighter colour shows that Alfred did remember to take out the cakes before they were totally incinerated!

The black variety can be very useful for lighting fires because the inner flesh, once dried out, can be easily lit from a “firesteel” (this is an “artificial flint” which creates a spark for starting fires, much used in bushcraft).  A spark will ignite the flesh of the fungus and, although it burns slowly like a barbecue briquette, once it has been lit one can transfer the glowing part to a ball of tinder and get a flame started.

Like so much in woodlands, once you know to look for these, you might see them  quite often.

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Hi, I have been trying to find an expert to remove permanently some king Alfred cakes that have ruined the floor of my narrowboat. I’ve just noticed another lady – Judy Ayton 22nd March 2009 – had the same problem, c.old anyone tell e if she solved the problem and if so, how.
Thank you
J. Ward

Julie Ward

3 December, 2017

[…] factoid from woodlands.co.uk: the inner flesh, once dried out, can be easily lit by a spark and, although it burns slowly like […]

[…] So off I set on my Marin mountain bike along one of the many tracks that follow the Great River Ouse. The evening sun filtered down between the tree tops as I cycled through ” The Thicket” – an ancient woodland of Ash and Maple. Looking up I saw a green Woodpecker flying to cover and a Robin spying on me as I sped towards St Ives. The Ash trees are known for a black bun-shaped fungus called “King Alfred Cakes” . […]

[…] 1. Daldina concentrica  – popularly known as King Alfred’s cakes (http://www.woodlands.co.uk/blog/conservation/king-alfreds-cake/) […]

Dear Judy (Judy Ayton, as above, – 10 posts ago)

How is your House Boat NOW ?

I’m asking becuase I want you to to be worried abourt seeing these ‘cakes’- which in your case are parasitic onto something which is keeping you afloat!

These fungi are metaphoricaly “sucking the life out” of YOUR wooden boat. What you and I can see is those ‘cakes’ which are the Fungal Fruiting Bodies of an organism that is actually MUCH, much bigger than just those cakes. Its a bit like the ‘tip-of-an-iceberg’, and there may be much ROTTEN wood.

This wood may literally “fail” suddenly, and there could be a great inrush of water ; and then loss of life/your home / whatever….

Please get it checked-out A.S.A.P. by a Professional ‘someone’ who can tell you ( and they may need to get some technical instrument/gadget onto the whole ‘suspect’ area ) – what the limit of the DECAY is ……..; how to remove it with SOUND wood.


3 November, 2010

Here is a very good method of igniting King Alfreds Cakes

Rumi Mohideen

24 September, 2010

I bought the swedish fire-steel army model and I think it’s a must have on a camping trip.

Jeff P

9 September, 2010

I found this information very helpfull and I would like to thank you !


6 September, 2010

I dry mine which grow on the fallen trees in my area. I wrap them in about 5 layers of news paper so anything alive in them stays in the wrappings them put them on a radiator again wrapped in an old tea towelfor a couple of weeks much to the wifes annoyance. I am a scout leader with the 14th spen valley scouts in west Yorkshire we have great success with these.


27 March, 2010

does any one have any tips on how to dry these out once you have found them?


17 July, 2009

i am also a explorer scout who’s (quite luckily for me) dad is actualy a leader of a group atm so i ave been quite lucky in the fact that i have been able to go on all the bushcraft / survival skills courses and i absloutly love it. the onmly problem i have with cramp balls is finding them because no matter how hard i look i cant seem to find them .

any tips on finding them?


13 May, 2009

hi, i am a 15 year old explorer scout and i find this stuff excellent for helping me light fires! could anyone give me any other ideas of things i can easily find out in the wild for lighting fires with?

Katie Roberts

4 May, 2009

and what problems could occur while i am drying them?


23 April, 2009

i have a few clumps but i need to how how long they will take to dry them and what would be the bwest way to dry them quickely any tips would be greatly apreiicated



23 April, 2009

Yes a very different fungus, but how do you get rid of it when it is growing on the wood on your canal boat. We have so far had three “clumps” of it.

Judy Ayton

22 March, 2009

type of plant i ment


15 March, 2009

Yes this website is very useful in fact i went on a walk today and found some.
But i would like to know if they have to be in season to grow or if they are just an all year round tupe of plant!?


15 March, 2009

Does anyone know how the mycelium affects the wood it runs through ones it has been cut down? It feels totally solid at the moment but sounds a bit hollow, and I am using it in a public setting, so need some information on the longevity. Can anybody help please? :)


6 January, 2009

I only recently started trying to light fire without matches. I find King Alfred cakes easy to do with either a fire steel or the magnifying glass on a compass. Horse’s hoof I find more difficult – am I doing the right thing? I cut it thinly (about half or a quarter of a cantimetre) then use either a fire steel or a magnifyer. I find it difficult to catch a light and doesn’t burn so hot when you blow it. Should I batter it to get it thinner? or soak it in something? I have also tried cutting it in 1 cm cubes but again, failed to get it alight. I do dry it for a couple of days first.

Edward Bainbridge

7 August, 2008

hi im a 14 year old scout and i love this stuff its helped me enormously even now in this time of year i still find king alfred’s cakes on birch trees. normally i would use horse hoof fungus but they are out of season now and i can’t find any. know of any other useful natural tinders that will light with a spark?


23 May, 2008

Here’s some more info, and magnified photos of paper produced from fungi:



12 April, 2007

ooh, I would love to know how to make paper with mushrooms…. do you know, is it just pulped in the same was as using old paper?

Tracy Pepler

6 April, 2007

Such mushrooms (perhaps not exactly the same type) are used to make paper in Norway and Sweden. I’m not sure about the practical value of doing so but the paper looks quite rustic with clear fibers – a pretty effect.

Hallvord R. M. Steen

4 April, 2007