This is one of the more straightforward areas of packaging and a pretty easy problem to solve. Many good bag suppliers will let you order sample packs or small samples of each bag type. There’ll be some trial and error with your sealing method and how to slide the cookies into the bag, so it’s worth getting some samples before you bulk order.
Pre-made Bags
If you’re bagging your cookies, i.e. pushing your cookie into a pre-made bag as shown above, simply measure the cookie at the widest point. Add 5-10mm to this size, to allow for variations in cookies and to make it easy to slide the cookie into the bag. You’re aiming for as tight a fit as possible, to reduce the air (moisture) in the bag, but you don’t want it to be a pain to try and get the cookie through the opening either. This measurement is the W (width) of the bag.
In the case of the Flat Bag and Zip Lock Bag above, if your cookie is very thick, it’s going to need even more width, beyond the diameter of the cookie, to allow the cookie to fit inside.
In this case you might be better with the Gusset Bag, it has the expanding sides to allow for thicker products. The depth of your cookie is your D measurement, plus a few millimetres.
If your cookies aren’t round (mine started out as rectangles, then round, then hexagons, it’s a funny story you can check out on my Podcast sometime), then you’ll need to measure the length as well.
If you’re using the flat bag and sealing them yourself, ensure you leave enough space to form a seal in your sealing machine. This isn’t just the width of the seal (the melted bit that sticks together), but the space needed to drape the bag over the machine or feed into the sealing wheels/arm of the machine. This takes a little trial and error to find the minimum amount of waste and an economical use of your time. You don’t want to spend ages trying to hold and feed, a tiny flap of plastic into your machine, when a few millimetres more will let you bag them quickly and easily.
A Note on Zip Lock Bags
In the case of the Zip Lock bag, make sure you have enough extra space between the cookie and the zip lock to be able to press it closed. If the cookie is too close, you won’t be able to get enough pressure on the zip to close it without crushing the edge of your cookie.
Also note that zip lock bags are more of a convenience for the customer than a guaranteed seal. This means you will need enough plastic above the zip lock to make your seal. Once the customer has broken the heat seal, they can then use the zip lock to keep your cookies fresh.
Stacked Cookies
Stacking cookies is a little trickier. The width of your widest cookie is your W (width) measurement.
Now stack your cookies one on top of the other and measure their height. This is NOT your L (length) measurement, at least not yet.
When you place your first cookie at the bottom of the bag, it won’t lie flat, because the bag is glued at the bottom into a V shaped taper. When you push the cookie down, more plastic will be pushed out to fit around the cookie, reducing the height of your bag.
If you stacked 5 cookies on top of each other and measured their height, you could find only 3 or 4 cookies actually fit in the bag. You’ll have to experiment with your sample bags to find the optimal length to fit your stack, plus room to seal the top. In this case the gusset bag could be a good solution
A Note on Gusset Bags
A gusset bag has extra folds which overlap. This means when you seal it, you’re sealing two different thicknesses at once, the overlapping edges and the straight edge. If your overlaps are too thick, your straight edge will melt before the gusset seals. Alternatively your edge will seal but your gusset won’t. A simple fix is to open the gusset out at the top, so you’re only sealing one thickness, but it’s an added step, increasing your bagging time.
Bag Sellers
There are loads of places to buy bags, but it’s good to have a reliable seller who can supply your business as you grow. If you’re just starting out and want to try lots of sizes, Amazon is great for flat bagging kits, zip lock bags and seasonal bags. When you’re ready to scale and need data sheets, I started with Polybags. They have a great range of bags and offer free samples for testing.
L-Sealer Film
Also known as Centre Fold Film or Bakery Film, this is a roll of material, folded along its length. You lift one side of the film and pop your product inside, then pull the lever down to form an L shaped seal around your product.
Like all automated or semi-automated systems, there’s a formula for everything. It will need tweaking to suit your machine, but hopefully this will get you started:
D is your cookie diameter. Times two is the diameter of the top and the diameter of the bottom.
H is your cookie height. Times two is the height of each “side” of the cookie.
≤3mm is a minimum but some machines may require at least 50mm to allow for the thickness of the arm to pass the side of your product. This is where the edges meet and the sealing wire melts them together.
In the case of my big cookies, they’re a maximum 150mm wide and 10mm high when cooked, so my formula looked like this:
150×2 + 10×2 + 50 (remember your BODMAS/PEDMAS from school?) 300+20+50mm = 370mm.
My L-sealer wrap was sold as 400/200. (It’s hard to find anything smaller). That’s 400mm wide when opened out flat and 200mm folded.
Go a little bigger if the size doesn’t quite fit. Too small and your edges won’t meet for sealing. Too big and you’ll have a flap which easily detaches as the seal is formed.
Flow Wrapper Measurements
Flow wrap film is sold in rolls by width. The length of your product is set on your sealing machine, so it’s irrelevant when purchasing your film.
D is your cookie diameter. Times two is the diameter of the top and the diameter of the bottom.
H is your cookie height. Times two is the height of each “side” of the cookie.
≤20mm is a minimum. This is the combined outer edges of the wrap, which are folded around the cookies and meet underneath. These two 10mm edges are heated and pressed together before being folded back onto your product to keep them lying flat. On most machines you’ll need at least 20mm to form a good seal and for the heated rollers to grip the plastic.
In the case of my shortbread biscuits, they’re a maximum 65mm wide and 10mm high when cooked, so my formula looked like this:
65×2 + 10×2 + 20 = 130+20+20mm = 170mm.
My flow wrap was sold in 200mm widths. Go a little bigger if the size doesn’t quite fit. Too small and you’ll be constantly re-feeding the wrap into your machine. Too big and you’ll have a larger flap under your product.
Bag and Film Thickness
If you’ve already started looking at bags or films, you might have been put off by the specifications and jargon, such as “20 micron centre folded polypropylene heat film, 1000 metres, plain, 600/300, 12″ wide, working size 300mm, 76mm core, co-extruded.”
Don’t be put off, it’s pretty easy to decipher, although the mix of US/Imperial and Metric sizes is a bit of a torture:
| Specification | Actual Meaning |
| 20 micron | Thickness of the plastic, trial and error will get you the bag you need but start with the outer dimensions first |
| Centre folded | L-sealer film |
| Polypropylene | The material the film is made of |
| Heat film | Suitable for heat sealing, i.e. Impulse sealer, L-sealer, Flow Wrapper |
| 1000 metres | The length of the roll of film |
| Plain | How the surface looks, some are crystal clear, some are clear, some are dull (cloudy) |
| 600/300 | On L-Sealer film these are the two sizes, unfolded and folded |
| 12″ wide | The width of the roll including the tube in the middle (core), this is important to know in case it doesn’t fit the roller that feeds your L-sealer |
| Working size 300mm | This is the folded size again |
| 76mm core | The diameter of the tube in the middle. Check it will fit your roller that feeds your sealing machine |
| Co-extruded | This means both sides of the film are coated, e.g. food safe, as opposed to lamination where only one side is coated |
| 7.27kg per roll | The weight of the roll affects your feed roller – what weight will it take? It also affects your storage/shelving capability when you buy it in bulk |
This is a photo of my flow wrap label.
- FXC is the type of film (coextruded BOPP film, heat sealable, suitable for food packaging)
- 25 is the thickness in microns.
- 200 is the width (mm)
- 1400 is the length of the roll (metres)
- 6.3 is the weight in kilograms
- 76 is the inside diameter of the core tube (mm)
- 230 is the outside diameter (mm)
The rest is batch coding, order numbers and dates for traceability. When it come to reordering, I would ask for 200mm polypropylene, or OPP200, the supplier’s code.
With your cookies bagged, the next step is labelling or boxing, depending on your target market, or maybe both. It’s another little minefield of options, but I’ll give you my fast track shortcuts to save you time and money.
How do you bag your cookies?
Do you use pre-made bags, or open bags and seal them yourself? Or maybe you’re at the L-sealer or flow wrap stage? Let me know your tips and tricks in the comments below.