# Custard **URL:** \ **Category:** First Cook Essentials\ **Created:** [May 22, 2020, 6:33am UTC](https://community.anovaculinary.com/t/custard/26085 "2020-05-22T06:33:08Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![RainaS](https://avatars.discourse-cdn.com/v4/letter/r/8c91f0/32.png) [@RainaS](https://community.anovaculinary.com/u/RainaS)\ **Post date:** [May 22, 2020, 6:33am UTC](https://community.anovaculinary.com/t/custard/26085/1 "2020-05-22T06:33:08Z")
I was looking at custard recipes and saw that they use mason jars, so of course, I bought something else. I bought custard cups with plastic lids. Now I realize my mistake, because while you can screw on a jar lid not too tightly, but with a plastic lid, if it’s on, it’s on all the way. Is there any way I can use them for sous vide? ---
**Author:** ![john.jcb](https://sea2.discourse-cdn.com/flex016/user_avatar/community.anovaculinary.com/john.jcb/32/7269_2.png) [@john.jcb](https://community.anovaculinary.com/u/john.jcb)\ **Post date:** [May 22, 2020, 12:30pm UTC](https://community.anovaculinary.com/t/custard/26085/2 "2020-05-22T12:30:28Z")
WHen the lid is screwed on tight the air that tries to expand as the temperature rises has no where to go. Very often the glass will shatter from the pressure. With the Ball type lids you tighten them finger tight. This allows the expanding air to escape while keeping out the water. I would not risk it if it were me. ---
**Author:** ![chatnoir](https://avatars.discourse-cdn.com/v4/letter/c/ecd19e/32.png) [@chatnoir](https://community.anovaculinary.com/u/chatnoir)\ **Post date:** [May 22, 2020, 1:20pm UTC](https://community.anovaculinary.com/t/custard/26085/3 "2020-05-22T13:20:42Z")
Raina, you could individually vacuum package the plastic cups and deal with the mess after processing. Of course, that’s not practical. If you are going to use recipes SV cooking requires attention to detail.