Roll-Top Insulated Lunch Bag
Posted on Wednesday the 17th June 2020 by Oak Blue Designs
Hello there! I’ve made a roll-top lunch bag that I’ve been looking forward to sharing about. For the pattern, I used a Roll-top/bento bag pattern from the shop SewtheLittleThings18, on Etsy. I have seen this style of bag used in kayaking and hiking applications.
The following two photos are from the pattern. I really appreciate that this pattern includes two size options:
There is also a sturdy bottom gusset feature incorporated into the design:
For the fabrics, I used a really fun quilting cotton print by Tim Holtz, from Minerva. The fabric print has multiple scanned documents that look like a collage of papers, printed on the fabric.
I also used a rust denim (that I made into a skirt with this post) and a newsprint canvas for the inner bag lining.
I used two layers of wool batting around the side of the lunchbag and one layer of batting along the bottom. With the added layers of wool batting, parts of this project ended up being more bulky to sew. I thought I’d note the sewing machine that I used for this project, for reference. I used a walking foot for most of this project (which helped with sewing the thick layers).
Insulated lunch bag PDF pattern by SewtheLittleThings18
0.7m Exterior Fabric A and B
0.5m Interior Fabric
0.5m Wool batting/Insulation
0.5m Lightweight woven interfacing, White
90/14 Universal needle
2.5cm x 90cm cotton webbing
2.5cm buckle clip
Large fabric sewing clips
The inspiration for this project was to explore handmade lunch bag sewing patterns. I want to make future lunch boxes for my kids to bring to school.
In the past I have been purchasing commercial lunchboxes for my kids to use. My experience has been that commercial lunch boxes are made really poorly. I should note that my kids bringing lunch boxes to and from school is more rough (wear wise). Last year was especially shocking as one of my kids went through four different lunch boxes. When I say “went through” I mean, four lunchboxes were worn out to the point beyond repair or mending and had to be replaced.
I wanted to share the suggested materials list from the pattern, for reference:
In hindsight, purchasing that many lunchboxes is not cheaper than making one myself (that will hopefully last all year, if not longer). I decided that I would test this idea by making a lunchbox for myself to use over the summer.
For this project, I made the larger size that is offered in the pattern. An Insul-Bright material is recommended to be used from the pattern. I thought it would be fun to go a different route for my version and use wool batting for a natural alternative. I added two layers of wool batting to the outer bag and one layer to the bottom of the bag.
I initially thought I would use the rust denim for the outer fabric. Once I received the fabrics in hand I fell in love with the Tim Holtz print. The lining fabric is mostly hidden so I decided to switch and use the denim for the lining.
I decided to apply the fusible interfacing to all of the fabrics. The denim is called out as an 10 oz weight on Art Gallery Fabrics website. I think the denim feels on the lighter end of a medium weight. I decided that adding interfacing couldn’t hurt (I didn’t want the bag to be floppy).
I had an issue with the document fabric (that was my own fault). I washed the fabric on a warm water cycle with a dark navy linen fabric included in the wash. The navy bled to the document fabric and changed the color tones from greys to purples and blues. I still like the final fabric but I wanted to note that my end fabric looks a slightly different than the original fabric.
As I was sewing the bag, I saw some variation in the corner edges. On the inner and outer portions of the bag, you can see a fold in some of the corners.This wasn’t a huge deal but I wanted to note this, for reference.
Along the bottom of the bag I had bulky seams and had to sew carefully. My machine could handle the layers but I wanted to note this for reference. The extra layers of wool batting added to the seam’s thickness (in addition to layers of denim and interfacing).
I wanted to note that I used a 5” length for the turning hole for the bag. The pattern called for a smaller turning opening but I needed to use a seam ripper to open up the turning hole to 5”.
I found a zipper foot handy to use when sewing the buckle clips onto the webbing.
I thought I’d note that I used a 5/8” webbing with a 1” clip for my bag. This webbing/clip size mismatch wasn’t intentional but I made it work for this bag.
I shared in my last post a photo of large fabric clips that were contained in a fabric bowl that I made. I have used smaller fabric clips in the past but these larger fabric clips were new to me. I LOVE using the larger clip size much more than the smaller size. They are much quicker for me to grab and clip onto fabric.
I wanted to test this sewing pattern for a lunch bag application. I also wanted to test using wool batting as a substitute for Insul-Bright insulation (for a natural alternative). I wanted to note that Insul-Bright, although a synthetic composite material is thinner and has a really good temperature insulation range.
Functionally, I really like this pattern and the design. Not having a zipper in this lunch bag means that it should last longer for myself and my kids.
Testing the bag:
To answer my wool batting replacement question, I decided to do an experiment. I was inspired by Dr Annie’s blog with her own commercial lunch bag testing.
I set up my testing in a similar format. I only ran this test once so this is a rough estimate of the internal temperature performance of the bag. I’m testing to see how long the lunch bag (with a freezer pack) keeps milk below 40 degrees Fehrenheit.
I used a glass Mason/Ball jar with a plastic lid and filled it with 1 cup of milk. I layed a blue freezer pack on top of the jar (inside the lunchbag) during the test. I used an infrared thermometer to take the temperature of the milk.
I took the temperature of the milk at the start of the test and again every two hours (stopping at 6 hours). 40 degrees F is a good reference to keep food at or below for food safety.
I wanted to note that for this test, the lunchbag was laying on the counter in our kitchen. For my normal lunchbag usage, I would be bringing the bag outside of our home (in environments that are typically hotter right now). I would expect the actual temperatures for my usage to be higher than observed in this test.
I noticed that the rolltop design has variation with how many times you could roll the top before snapping the buckle clips together. If there are taller items inside the lunch bag, you’ll have less room to roll the top of the bag for closure. If the items in the bag are shorter, you could roll the bag more times before snapping the clips (for a better seal and more layers of insulation).
I really like this design. I would like to try making this bag again for my kids but try Insul-Bright instead of wool batting. I love that wool batting is an option and I enjoyed trying it for this project. If you’re one that brings your lunchbox to work and have a short commute, the materials used for this bag will work just fine. If you have a longer period of time that your lunchbag will not be refrigerated (before being eaten), then you may want to try alternate insulation materials as well.
Thank you so much for reading! Let me know if you’ve made a lunch bag of your own and if you’ve had any designs or materials that you’ve enjoyed pairing together.