Closures: A Quick and Easy Guide 

Saia Wholesale Containers carries a wide variety of glass jars, bottles, and jugs. Despite their diversity, they have many things in common: they’re made in America, they’re affordable *wink*, and they all need closures.

Closures, or lids, are not always straightforward, though. How do you know what size to get? Are there different types of closures? Should you use a metal closure for your product, or should you consider plastic? We’re here to clear a few things up for you and help point you in the right direction. 

A gift certificate with a floral design on it.

What many people are used to seeing available for home canning are the two-piece lids that come with mason jars. There’s no doubt that these lids are useful (there’s a reason they’re so popular!), but they come with their own fair share of issues: two pieces mean twice as much to keep up with, dents are becoming increasingly more common straight out of the factory, the amount and quality of sealing compound can vary widely, and newer lids are often thinner and flimsier than their vintage ancestors. For these reasons, Saia Wholesale Containers only carries one-piece closures. This keeps shipping costs down for us and our customers and helps us ensure the quality of our products.  

Closure Styles 

Let’s talk about the two different kinds of closures we offer: continuous thread (CT) and lug. Continuous thread is the standard in home canning. These closures are slightly taller in height than their lug counterparts and are threaded in one continuous bead to match their corresponding container. Lug closures, however, are designed for a quick, easy close. They require less than a full turn to secure and have evenly-spaced tabs at the bottom of their threading to interlock with the corresponding container’s lug-style finish. Here you can see a comparison. Our 70-450 black metal continuous thread button closure is on the left and our black lug-finish 63-2030 closure is on the right. 

A gift certificate with a floral design on it.
A gift certificate with a floral design on it.

Continuous Thread……….Lug

How They Are Measured 

You may have noticed the different numbers in the closure descriptions. These are simply measurements. The first number (usually two digits but sometimes three) refers to the width or diameter in millimeters; the second number (three or four digits) refers to the height and the style of the threads. Standard regular mouth canning jars use 70mm with 450 finish (70-450) lids, to give you an example. We carry sizes from 18mm to fit our 1.5oz Woozy bottles to 110mm for our gallon-size jars. To make this easy for our customers, we have linked corresponding closures to our container product pages in the Related Products section. You can also find the closure size for each container in the Specifications Table on the product page, as seen here: 

A gift certificate with a floral design on it.

Material 

There are two main materials that lids are made from: metal and plastic. As you may have guessed, only the metal ones are used for pressure or water bath canning; the plastic caps can be used for “hot fill” products. All our metal closures come with a plastisol liner for sealing. Plastic closures often come with a foam or plastic liner. It’s important to identify which kind you will need for your products before you “Add to Cart”. 

To Button or Not to Button? 

You may have noticed that some lids come with what is called a “button” while others do not. What’s the big difference? Surprisingly, there isn’t much difference between the two. They both seal the same, but it’s easier to see when a jar has sealed if there’s some sort of indicator. Many people can see the difference in a buttonless closure that has sealed, but using a button closure can add the comfort of assurance. This feature is specific to metal closures, as is the “High Heat option, used for pressure canning or water bath greater that 15 minutes. You may also use a button closure for water bath less than 15 minutes.

High Heat Closures 

One last significant difference in types of metal closures is “High Heat” versus low heat, also known as “Home Canner“. Low heat lids are lined with your standard plastisol and can be water bathed up to 15 minutes but are not recommended for use in pressure canning. High heat lids are lined with a plastisol that has been formulated to withstand higher temperatures, making them a much safer option for water bath canning longer than 15 minutes and an ideal choice for pressure canning. 

Finally, a Word from Our Founder 

Mr. Steve Saia, founder and owner of Saia Wholesale Containers, offers us this word of assurance: 

One-piece commercial grade, plastisol lined closures are the single most affordable option for all your canning needs.” 

Now that you know how to select your lids, you can hop over to the Shop page to get started on your order! Remember, you can find corresponding lids for our containers in the “Related Products” section on the product page.