What is contract bottling and why should you use a bottling service?

What is contract bottling? (Contract bottling)

What is contract bottling?

Contract bottling is hiring another company (known as a contract packer or co-packer) to bottle your product for you.

Normally, the bottling company will handle the entire packing process, not just the bottling. That means putting the liquid product into bottles and providing further packaging for distribution if you need it. A contract packer can also advise you on what kind of bottle is best for your product.

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Why use a contract bottling service?

Employing a contract bottling company allows you to control costs.

Bottling machinery and equipment can be tricky to set up and maintain, and needs to be operated by properly trained personnel. This is all very expensive to put in place.

If you decide to introduce a new product, bottling it means either buying more equipment or disrupting your current production line. Using a bottling company avoids both these issues and gives you far more flexibility.

What does contract bottling involve?

If you employ a contract bottling company to do your bottling, this is typically how the process goes:

1. You decide what liquid will be bottled and what ingredients go into its formulation.
2 You deliver the product to the company. This can be in large vats, barrels, tubs etc.
3 The bottling company does a visual check of the product for quality control purposes.
4 You choose:
a bottle, jar, tub or other container for the liquid to go into
a cap or other closure for the container to be secured

The company then orders these items for when production starts.

5. You choose the labels or screen printing for your chosen container.
6. The company agrees on how much liquid will go into the container (volume) and the level to which the containers will be filled. (Most bottling companies work to minimum weights or volumes.)
7. The bottling company makes a sample for you to approve (often via a photo).
8. The bottling company begins the filling process, applies the labels or printing to the containers, fits and tightens the caps or other closure and prints a date code onto the container.
9. The bottling company packs the product in boxes. This is usually in printed individual cartons or in bulk, depending on what you need. If the product needs an overwrap (think of how perfume is packaged) or shrink wrap, that will be applied last of all.

Watch a video of WePack’s bottling machine in action:


Why do we need a bottling company? Can’t we do it ourselves?

If you’re handling only very small quantities, you can do the bottling yourself using basic equipment like a funnel and a jug. If you start to increase the quantities you produce, that’s when you might decide to use a contract bottling service.

Most contract bottling companies have a minimum order charge. So, as you grow, moving from a smaller set-up to something more industrial begins to make more sense.

What types of products can a bottling company bottle?

Bottling companies will typically bottle:

  • flammables and non-flammables
  • lotions, gels and creams
  • thin pastes
  • honey
  • syrups
  • serums
  • concentrates
  • cordials and soft drinks
  • beer and wine
  • oils
  • detergent
  • food and non-food products


What type of bottle is most suitable for our product?

The bottle you choose for your product depends on:

  • what your product is made of
  • the message you want your brand to communicate
  • how heavy the finished item will be to transport
  • any safety considerations that apply
  • cost

These all affect the decisions you make about:

  • material (usually plastic or glass)
  • colour
  • design and look
  • print
  • size and volume (how much liquid the bottle should hold)


Should we choose plastic or glass?

The ingredients or chemicals that make up the product dictate whether the bottle should be plastic or glass.

Most plastics are porous (have very tiny holes in them), meaning strong scents can escape and air can seep in. Oxygen getting into a bottle can cause some liquids (such as alcoholic drinks) to go off or can shorten their shelf life. A product like perfume has a very potent scent that would leak through a plastic bottle.

It’s been claimed that plastic also has chemicals within it that break down over time and leach into the liquid inside the bottle. Studies have shown that it’s possible for very small amounts of chemicals to get into food and drink this way, but at no level that would be considered anywhere near unsafe. Indeed, the UK has very strict regulations about plastics that are used for food or drink.

Glass, however, doesn’t have these problems, and is the reason why many alcoholic drinks and strong-scented liquids are contained in glass bottles.

If your product has a strong colour or is made from certain chemicals, it can be affected by the UV light found in sunlight. In these cases, we would use coloured glass to store the liquid. Amber-coloured glass, for instance, blocks out the UV rays and helps keep the product in its best condition for longer.

What is gas flushing?

Gas flushing (also known as florination) is repeatedly injecting an inert gas (carbon dioxide or nitrogen) into the packaging and flushing it out so it takes all the oxygen with it. This helps to extend the product’s shelf life and condition and can protect it from damage.

Bottling companies tend to do this for bottles carrying solvents such as nail polish remover. The bottles are placed in a special chamber. The chamber is filled with a gas which hardens the bottles’ internal walls and seals off their pores, stopping scents from escaping.

Gas flushing also helps prevent “panelling”, which is when the bottle dimples and its walls begin to break down over time.

How does bottling work with unusual shapes of bottles?

For bottles with unusual shapes, the bottling company might use semi-automatic production lines (i.e. when part of the job is done by machines, part of it by workers), as fully automatic lines can’t accommodate them. This enables it to handle any shape of bottle, in principle.

How do we choose a bottle cap and closure?

A bottle’s cap must fit perfectly so none of the liquid can leak and nothing can get in that will contaminate the contents. Caps and bottlenecks need to match in terms of size and thread (the ridge around the neck that allows the cap to be screwed and tightened) so the bottles can be closed securely.

Types of bottle cap

The table below shows what types of bottle caps are available, and the circumstances in which you might choose them.


Type of cap

Screw top


  • Most common type of cap
  • Usually plastic but sometimes metal
  • Fastened and unfastened with several turns
  • Easy to tailor to branding and bottle shape
  • Can be made child-resistant with special safety mechanism


Often used for

  • Soft drinks
  • Tablets
  • Household cleaning products (e.g. bleach)


Twist top

  • Usually metal
  • Most often used with glass jars
  • Fastened and unfastened with a quarter turn
  • Preserves (e.g. jam, marmalade)
  • Pickled foods (e.g. onions, beetroot)

Flip top/press top

  • Small hole for dispensing the contents
  • Usually used with squeezable plastic bottles
  • Condiments (e.g. ketchup)
  • Beauty products (e.g. lotions)

Spout top

  • Usually plastic
  • Spout for dispensing
  • Small cap to prevent leakage, often attached


  • Superglue
  • DIY products
  • Hair dye


Pourer cap

  • Usually used with thin plastic or glass bottles
  • Has a funnel that allows contents to be dispensed sparingly or drizzled
  • Two types a long spout or with a cap and rubber funnel


  • Cooking oils
  • Condiments (e.g. sauces)



  • Usually used with small glass bottles
  • A thin glass or plastic tube with a cap and squeezy rubber bulb to suck up the liquid
  • Medicines (e.g. eyedrops, vitamins)
  • Cosmetics


  • Usually used with thin-necked bottles
  • Caps that plug the bottle until they are lifted off or pulled out
  • Some have a metal clasp to hold them in place
  • Alcoholic drinks
  • Cooking oils

Atomiser (spray)

  • Operated by pushing down the cap to produce a fine spray
  • Some have a trigger that lets you spray the liquid across a wider area
  • Some products have a lock in the cap so the spray can be blocked (helpful to stop young children using them)
  • Cleaning products (e.g. for windows, kitchen surfaces)
  • Cosmetics
  • Medicines (e.g. for sore throats)

Pump top

  • Like atomisers, they’re operated by pushing down the cap
  • However, pumps are designed for thicker liquids rather than fine sprays
  • Some have a spout
  • Some incorporate a lock to stop them from being pumped accidentally


  • Cosmetics (e.g. suntan lotion)
  • Household products (e.g. handwash)


Crown cap

  • Usually metal
  • Crimped into position around the head of the bottle
  • Some can be unfastened by hand, others need an opener
  • Alcoholic drinks

Neck finishes

Whichever bottle and cap you choose must have a corresponding closure. In other words, the thread pattern on both the inner cap and the neck of the bottle must match so the cap can be screwed on and tightened properly.

There are several thread styles that serve as the established standard across the glass and plastics industries. The main difference between them is the number of turns it takes to tighten the cap. The bottling company will usually give you the option of choosing a neck finish and thread for your bottle.

How does labelling work?

At WePack, we label most bottles by hand because of their shape. Sometimes we use machines, although you’d need to provide your labels on rolls in the correct orientation for this to be possible. If you send us your artwork, we can print the labels ourselves, giving you one less thing to worry about.

What does contract bottling cost?

Prices vary between bottling companies.

To find out about cost considerations for bottling services.

Find out more

To find out more about contract bottling please contact WePack on 0115 852 9000 or get in touch via the form below.