How to sew a hidden gusset
A brief usually has two style of gussets, an open gusset or a hidden gusset.
An open gusset is where there is no seam on the front of the briefs and you are able to get your fingers between the inner gusset and front of the briefs on the inside. The gusset top is usually left raw, overlocked, or I have seen it where some brands have put fold-over elastic on top to finish it off.
A hidden gusset is where there is a back seam and a front seam and you can not see any of the seams on the inside.
I personally like to design all my briefs with hidden gussets, I think it looks better finished, your fabric goes further, as you are not juggling laying big fronts on the fabric. Also through wear and tear the gusset stays flatter through washes and doesn’t twist and roll up.
There are a couple of ways to sew a hidden gusset, one below and also sewing where you twist the inner gusset over but I find that can be quite confusing and if you don’t get it right the inner gusset is twisted and not flat and you have to unpick and start again.
If you wish to print this off from the image below you are more than welcome to have it as a reference.
I have used different colour fabric pieces so you can see exactly what is being sewn onto what.
I usually start with the front pieces first, you are sandwiching the front panel of fabric.
Lay the inner gusset ‘right side up’
Lay the front panel on top of gusset ‘right side up’
Lay the inner gusset ‘right side down’ on top of front panel
Sew
Lay down the front panel brief with the gusset furthest away from you ‘right side up’
Lay the back panel ‘right side down’ on top of gusset
Roll up the back panel
Roll up the front panel
Pull out inner gusset from underneath and flip over the front and back rolled pieces
Sew gussets and back panel together (the back panel is sandwiched between the gussets)
Pull out front and back panel
Unroll and ta daaaaa…… you’ve just sewn a hidden gusset.