When choosing a bit you should always think about the mouthpiece material as well as fit, side style and mouthpiece type.
The mouthpiece is the part of the bit that goes into the horses mouth and can be made up of a number of different materials.
Stainless steel
Most bits now are made from stainless steel 18, which is an alloy of iron, nickel and chrome. It is cheap to mass produce, strong, easy to clean and doesn't rust. You may see some rusting to bits, this is poor quality chrome plated steel rather than Stainless Steel.
Stainless steel is neutral tasting and doesn't encourage nor discourage salivation.
High copper content
High copper content bits are an extremely popular choice with horse owners. Generally these bits are varying shades of gold depending on the content of copper and other metal alloys used.
These bits are a warmer meaning they adapt to the temperature around them and warm quickly in the mouth to the horses body temperature.
Copper mouthpieces are great for dry mouths and those that need encroachment to salivate and respond to the bit.
The copper material is softer and so tooth marks can usually be seen in them which they are poorly fitted. It doesn't generally create sharp edges but we don't want the bit to hit the teeth so do have a look at how your bit is fitted if this happens.
Mixing copper with other alloys makes these bits more durable, such as brass bits, "German Silver" which is a copper, nickel and zinc alloy, Neue Schule and Sprenger Bits.
Neue Schule Salox and Sprenger aurigan and sensogan
Both Neue Schule and Sprenger have their own branded metal alloy. They are both copper based with trade secrets mixed in.
Neue Schule Salox possesses a high thermal conductivity and so warms up quickly within the horses mouth. Salox differs from standard stainless steel and other copper alloy bits in that it is a slightly softer metal, allowing it to safely absorb impact forces whilst protecting tooth enamel. This can make the mouthpiece easier to accept by the horse.
Neue Schule aims to keep the bit comfortable but neutral in the horse’s mouth. We don’t want our horses to inwardly fixate on the bit, but instead be receptive to all our aids. A mouthpiece that doesn’t taste or emit a smell is one that will remain neutral in the mouth- after all we don’t want our horses chomping and sucking at the bit because it tastes.
There is no evidence that over salivation means the horse is accepting the bit, and the horse cannot physically swallow this excess saliva and breath at the same time. Over-salivation may therefore impact on performance, particularly during faster work.
https://nsbits.com/knowledge_base/salox-sound-science-good-sense
SENSOGAN
SENSOGAN – the new bit material developed by SPRENGER – is the result of additional development and consequently the improvement of our original material, Aurigan. We have built on the success and positive features of Aurigan, specifically the taste and salivation aspects to give an even more delicate and sophisticated connection to the horse. It is the distinctive composition of copper, manganese and zinc that makes SENSOGAN so special. With a reduced copper content the oxidation process is still maintained, however, the extraordinary combination with manganese is what makes the difference. This combination results in a smoother and more regulated process of oxidation. Tests show a very positive infl uence on the horse’s satisfaction, motivation and willingness to perform.
The copper discharge quantity into the horse’s saliva is reduced considerably, which helps to keep the noble white-gold colour for a longer time. The new ingredient manganese on the other hand is an important micronutrient. As a crucial component and activator of enzymes, manganese is highly relevant for building up connective tissue as well as for the muscle and energy metabolism. It can therefore be helpful in preventing muscle tension and in supporting stress reduction. Beyond that, manganese is needed for the reduction of histamine and can prevent allergic skin reactions. Also, the feed industry discovered manganese to be a promising food additive that is gaining in importance in modern feeding of sport horses. https://pferdesport.sprenger.de/en/quality-brands/sprenger-brands/?
Sweet iron
Another very popular choice, sweet iron is generally black or blue when new and will always rust. Many people are put off by putting a rusty bit in their horses mouth but this is the whole point if these bits. When rusting, they create a taste which encourages salivation and acceptance of the bit.
To care for a sweet iron bit it's best to wipe it with bit wipes rather than use a lot of water and soaps. Use an olive oil soaked cloth after cleaning to maintain and reduce the rapid rusting of these bits.
Plastic, rubber and synthetic materials
Synthetic bits are great for youngsters, sensitive and fussy horses that don't like metal in their mouth. They come in a variety of colours and harnesses, from very bendy to very hard to suit your horses needs. Some synthetic mouthpieces come quite thick, around 20mm, this may be too thick for some horses but generally horses are very accepting of a synthetic bit.
Nowadays you can get anatomically shaped plastic like the Beris Konnex bits that lie flat and hug the tongue creating a comfortable even pressure throughout the mouth.
Happy mouth straight bar bits tend to have two raised bobbles. These are not dressage legal as the bobbles are very hard and dig into the tongue and roof of the mouth.
You should take care to research what is at tge core of the bit and ensure you use one which has a steel cable core. These bits are very prone to being chewed and tooth marks, this is only if the bit is incorrectly fitted. I had a nathe and beris bit for my mares and neither ever chewed it. Do always take care to maintain this type of bit as sharp edges will cause problems in the mouth and should immediately be replaced. If your bit is being chewed then check the position of the bit in the mouth as it shouldnt be touching your horses teeth.
Leather
Leather mouthpieces become soft when in contact with warm saliva, this means the bit will mould to the contours of the horses mouth. They are great for sensitive, young and fussy mouths. They are a great way to enhance communication and relieve pressure within the mouth and discomfort from metal bits.
To maintain this bit from drying out and cracking you should regularly apply olive oil to keep it supple.
Also always fit the stitching to the front incisor teeth.
Titanium
This metal is becoming increasingly more popular and is very light weight. It has antibacterial properties and is very compatible with horses mouths. It encourages salivation production and is a warm metal, enhancing acceptance. They are extremely strong bits, never rust, nickel free, hypoallergenic and non-toxic.
They are great bits for sensitive mouths, horses that react to other metals, (showing red rash or sores dispite the bit fitting correctly and light rider hands). The lightness of these bits give quicker response to aids than heavy bits.
Older bits - steel and nickel
Older bits were made from steel, this was cheap but had a tendency to rust very quickly. In the UK before most manufacturers started to use stainless steel, nickel was cheap and an easy material to use.
Nickel generally has an olive colour and never rusts, however, it is a soft material and many antique bits you see made from nickel have stretched joints or distorted rings. They make great decorative pieces nowadays as these edges can be sharp and they don't look as nice as shiny stainless steel bits.
Nickel can also cause allergies so has widely stopped being produced. Abbey Bits still manufacture Kangaroo bits which are made from a nickel alloy.
Aluminium
Very few bits are made from aluminium, Mikmar bits are made from this metal. They are very bulky bits so aluminium is a good choice as other metals would make the bit too heavy. However, aluminium is considered to dry the mouth out and may be toxic to horses therefore isn't used in bits.