The Gall of It All

Enter the Oak Gall.  Provider of tannic acid for centuries past and up through today.  The Oak Gall is the “gall” part of “iron gall ink.”  So, what is an oak gall?  What does it look like?  How do I obtain oak galls?  Do oak galls have other names they get called?  Do all galls have the same amount of tannic acid in them?  All good questions.

Oak galls grow on oak trees.  I realize that sounds rather obvious.  Sometimes though the objects name is misleading so I wanted to be clear about that with you.  The oak tree is any of 207 trees or shrubs in the genus Quercus and is in the beech family.  Quercus is the Latin for “oak tree” unsurprisingly.

So where to oak trees grow?  Oaks grow in many different places and climates.  In the USA the oak in some form is prevalent throughout the country.  You can buy books on tree identification that will show you the geographical range of various kinds of trees including oak trees.

The oak gall is just one of many kinds of galls.  A gall is a plants reaction to infection creating a growth to battle that infection.  Many plants produce galls. And no, not all galls look alike or are useful for the purposes of making ink.  Here is a lovely article discussing all sorts of galls.  For our purposes we want the galls created by insects laying their eggs in the leaf buds.  Number six in the linked article shows some California “oak apples”.

Yes, oak galls do have different names.  A few of the names I have run across are “oak apples” and “oak marbles,” and “gall nuts” even though they are not a nut of any kind nor an apple of any kind.  Sometimes in the pre-17th century recipes we simply see them called “galls”.

How do I obtain oak galls?  You can purchase them and you can go pick them off the tree or the ground if you find them there.  Of course your friends can pick them off the tree for you and give them to you as presents also.  Picking oak galls does not harm the oak tree.

What do oak galls look like?  This wikipedia article, yes, I know, actually shows a very good assortment of various oak galls.  It is actually supposed to be a discussion of one kind of insect that causes oak galls and is heavy on showing the oak galls.  It also points to a truth of collecting oak galls for yourself.  To get the insect caused leaf galls we are after you first need to have the insects that create them.  If your city sprays insecticides to get rid of mosquitoes (and considering the diseases mosquitoes can give you that can be a very smart thing for them to do,) they might be killing off the insects that create oak galls.

I have a collection of galls that I keep both to make ink with and as a display to help people identify galls when they see them.


Oak gall attached to tree branch.

This one fell from the tree I happened to be next to when I was at the park.


A closer look

You can see that the other leaves are healthy which in my experience is typical.  This gall is still a bit green but is also drying out to the beige color you usually see on this kind of gall.


A closer view of the gall

Galls are attached to the tree via a stem just like leaves are.  It makes sense that they would be.

This gall is from Oklahoma.  I have galls from Indiana that look very much the same but have dried out.


Detached dried out gall

These galls are typical of red and white oak varieties.  You may have noticed the hole prominently displayed in the picture.  That hole is where the insect larvae ate its way out after hatching.  Generally speaking galls with these holes are better for our use.  Of course sometimes we are going to pick galls without the holes in them.  I generally prefer to put the galls I harvested in the freezer in a ziploc container for a week before bringing them back out.  This kills any insects that might be in there.

So what are the properties of this kind of oak gall?  Well they are fragile, have a papery outer layer and are mostly filled with air and some fluff that contains most of the tannic acid.  You can easily crumble these in your hand.


Outside focus


Inside focus

You can see that there is some stringy fluffy bits in there.  Let’s get a better look at that.


A separate gall showing the “empty” insides of the gall

The white fluff is connective tissue inside the gall.  No reason to get rid of it.

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With the tannic acid bundle

I don’t know the technical term for the brown bundle so I call it a bundle.  It contains most of the tannic acid in the gall.  This one fell out.


Giving you an idea of how much of this kind of  gall is actually hallow.

This is roughly how the gall might look if you open it up.


Some size measurement for you.

These are typical galls in size and coloration.  Hopefully this helps you if you go out to harvest them yourself.  Keep in mind that not all galls are the same.


Twig or branch galls

These are also oak galls. As their name implies they are grows in the twig or branch. They are not very useful for our purposes of making ink. Yes they have tannic acid in them but extracting that out is not a very efficient process.  Avoid these galls as they are not going to work well for you.

If you happen to live around live oaks you can get oak galls from them as well.  For those who don’t know the live oak is a broad leafed evergreen oak.  They don’t lose their leaves like other trees do but they have deciduous leaves unlike the “needles” from coniferous trees such as pines.

The galls from live oaks look entirely different from the galls above.


Live Oak Galls

Live oak galls are smaller and can be a dark to light brown coloration.  They are mostly smooth and are dense and hard in consistency. It takes a mortar and pestle, hammer or other smashing implement to break these galls up.  I’ve used these galls to make ink with varied results.

If you pick these galls from the tree they contain an acceptable amount of tannic acid in my experience. They are very good for making inks.  If you pick these galls up from the ground I have found they leach out their tannic acid very easily to rain and other environmental factors.  So picking them up from the ground generally means they will be of lower quality.  Just make sure you know what you are getting yourself into and adjust accordingly.

In period and today there is a gall that is considered best.

The Aleppo Oak Gall.


Aleppo Oak Galls

These are small dense, very hard galls.  In period and today they are considered the premium type of oak gall.  They come from the Aleppo Oak (Quercus infectoria) that is found in the greater Syrian region that covers in part, Syria, Turkey, Iraq, Jordan and Israel.


Aleppo Galls with ruler

Aleppo galls are my preferred gall to make inks with.  I generally purchase them from John Neal Bookseller.

Oak galls all have varying levels of tannic acid in them.  Typically speaking the aleppo gall content is 65 – 75% tannic acid.  Galls from Europe and Britain content is typically 55 – 65% tannic acid.  Galls from North America are typically 45 – 55% tannic acid.  So make sure you note that when you are making your inks.  Sometimes you need to do some math to adjust the amount of galls you need from the recipe depending on what kind of galls the recipe calls for and what kind of galls you actually have.

I hope this informational field guide to oak galls is useful to you.

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