Should I Spit Saliva on my Fly Fishing Knots? Explained

Watch any lesson on how to tie fly fishing knots, and you’ll be told to spit on them before clinching them down.  But why?  Is this really necessary? What are the alternatives?

The practice comes from a time when fishing nylon had a rougher surface than it has today.  

Most angling experts recommend wetting knots with spit (saliva) when tying on a fly, or connecting leader and tippet materials.  Fly fishing knots need to be lubricated so the knot seats correctly and to remove friction in the line – both of which weaken knots. 

Knots that don’t seat correctly form a weak spot, as does a dry line submitted to the friction created when tightening the knot. 

Here’s how it works. 

Why Spit on my Fishing Knots?

Spitting on your fly fishing knots before you sinch them down is an old tradition.  It stems from the days when nylon or monofilament fly line was made with a less slippery exterior.  

Today, all lines are produced to a smooth finish. However, the practice continues, despite some controversy between experts.

Spitting, or covering your fly line in saliva, as you complete the knot is still practiced today, and that was how I was taught.  

Does Spitting on Fishing Knots Make a Difference?

There are two key reasons to spit saliva on your knots.

Lubricated knots are likely to seat properly

Knots need to seat properly to make the knot the strongest and, therefore, the most effective.  

Wetting the knot allows the twists and turns to slide over themselves.

Knots in line that have a wet surface will allow the line to slide down on itself.  The lubricating nature of your saliva ensures that this happens more easily.

Tightening a knot with a quick jerk can cause part of the knot to lock up while not allowing the rest to seat properly, resulting in a weak knot.

Gradually pulling the knot tight to get it seated properly is key, followed by a very firm pull to set the knot. 

Wetting the knot with your spit before tightening will help it seat properly, giving the knot greater strength.

Saliva protects a knot when tightened too quickly

Sinching down knots too quickly can create heat in the line, which causes it to weaken. 

It is friction that causes the line to weaken.  Applying saliva will help reduce the friction. 

Here’s a test that proves it’s not a ‘hairy fairy’ idea.  It shows how easy it is to weaken a line by rubbing the line with a cloth.  

The solution is to apply even pressure when tightening your knots.  

Friction can cause a lot of heat when tightening knots which causes a tippet that is in good condition to quickly lose its integrity, resulting in losing your fish!   

Practicing your knot tying at home is a great idea.

When you’re rushing to change your fly in the excitement of catching that big brown trout you can see feeding on the surface, it’s easy to rush the last piece - sinching down the knot.

And doing in the wind and rain can be an extra trial.  Practicing at home before you hit the water can give you a huge advantage. 

Are all knots the same when it comes to applying saliva?

There are many variables when it comes to tying and sinching knots.  And then there is the case of which lubricant is better.

From the research I’ve done, it appears that all knots can bring different results.  

There are many variables, including the:

  • Way the knot is seated
  • Type of line 
  • Movement within the knot when in use
  • Uneven pressure on the knot when tightening
  • Speed of the line when sinched up
  • Type of lubricant
  • Bad luck

Why use saliva and not water to wet fly fishing knots

Saliva can decrease friction force by at least 2 orders of magnitude when in-between hydrophobic surfaces such as a nylon or monofilament fishing line. 

Saliva forms a thin acellular organic film (the salivary pellicle) on any surface exposed to saliva. 

There are many reasons for this organic film.  It makes our food taste better and protects us from bacteria, but it’s the lubricating effect that is most valuable to fishing. 

Some people use the water from the river or stream, but as you can see, this is not as effective as your own spit. 

If you are worried about picking up bacteria from your fly line, then you can use water, but it won’t be as slippery and, therefore, not a good lubricant.  

Three Alternatives to Spitting on Your Fishing Knots

Lip balm

Some people use lip balm or chapstick to lubricate their fishing knots.

It works, and in most instructional videos I’ve reviewed like this one from Orvis, it is better than nothing.

However, I’m cautious when applying any chemicals to my fly line.  

Sunblock is a killer for synthetic lines, and there are usually sunblock chemicals in lip balm and chapsticks.

Sunscreen will break down your fishing line and put a negative film onto your fishing lure.

I’m also very wary that fish can ‘smell’ the chemicals in my sunblock and chapstick.  

Many substances that anglers suspect deter fish from biting lures (e.g., insect repellant, sunscreen, fuel) are not water-soluble which greatly reduces the chances of them getting into the fish’s olfactory system. 

But I’m not willing to test it out.  I don’t catch enough fish as it is. ?

However, if you prefer not to lick your line, lip balm and chapstick will lubricate your knots.

Be careful to wipe off any residue, as any chapstick lubricant left on the line is more likely to pick up dirt. 

Water from the river

Many people prefer to use water rather than spit on their knots to reduce contact with possible bacteria in the river or lake water.

River and lake water may contain pollution that you don’t want to ingest. 

I wouldn’t be keen to keep a fish from these waters.  So the ideal situation is to fish where I know the water is clean.

However, contaminated water can happen anywhere.  

You’re taking a minimal risk with using river or lake water on your knots.  But as you are likely to be wading in it anyway, I don’t see this as a risk.

The main thing is that saliva is twice a good a lubricant as described above. 

Silicone fly floatant

Some anglers use fly floatant, silicone line cleaner or similar products on their knots. 

This practice does not seem very common as there were few tests or reviews for this way of lubricating knots. 

I can see that it would help with helping a knot seat well, but not sure about its other effects.