# Prime rib roast
**URL:** https://community.anovaculinary.com/t/prime-rib-roast/24261
**Category:** First Cook Essentials
**Created:** [December 22, 2019, 9:03pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261 "2019-12-22T21:03:59Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@docwas](https://community.anovaculinary.com/u/docwas)
#### Post date: [December 22, 2019, 9:03pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/1 "2019-12-22T21:03:59Z")
I am planning to SV a prime rib roast that is 3 ribs, but weighs 10 pounds. My wife will only eat medium, so I am planning to set the temp at 138F. How long to I need to SV it/?
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### Author:  [@Ember](https://community.anovaculinary.com/u/Ember)
#### Post date: [December 23, 2019, 8:17am UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/2 "2019-12-23T08:17:23Z")
Size? Dimensions matter, not weight.
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### Author:  [@chatnoir](https://community.anovaculinary.com/u/chatnoir)
#### Post date: [December 23, 2019, 12:04pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/3 "2019-12-23T12:04:09Z")
Hey Doc, please see my response to workerbee.
You realize the temeprature you selected is at the low side of Medium.
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### Author:  [@docwas](https://community.anovaculinary.com/u/docwas)
#### Post date: [December 23, 2019, 6:05pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/4 "2019-12-23T18:05:22Z")
Ember, the roast is roughly oval, with 8" in the long direction and 6" in the short direction. It is 7" long. I guess the controlling dimension is 6". Most of the things I can find about “thickness” don’t include a dimension of 6".
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### Author:  [@docwas](https://community.anovaculinary.com/u/docwas)
#### Post date: [December 23, 2019, 6:07pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/5 "2019-12-23T18:07:39Z")
Chatnoir, How do I find your response to workerbee?
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### Author:  [@Ember](https://community.anovaculinary.com/u/Ember)
#### Post date: [December 23, 2019, 8:37pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/6 "2019-12-23T20:37:13Z")
OK. Thank you. Sous vide (in fact all cooking) is about heat penetration. It is thickness that will be your guiding factor for calculating the duration of cook. A prime cut like a ribeye roast will require being brought up to your doneness temperature and little more. You’re going to be looking at over 14 hours just to get your roast up to temperature at the core.
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### Author:  [@chatnoir](https://community.anovaculinary.com/u/chatnoir)
#### Post date: [December 23, 2019, 11:08pm UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/7 "2019-12-23T23:08:08Z")
Doc, it’s this one.
**20 Lbs Prime Rib Roast - Boneless**
I regret the confusion. I’m a forum novice and it certainly shows.
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### Author:  [@docwas](https://community.anovaculinary.com/u/docwas)
#### Post date: [December 24, 2019, 3:36am UTC](https://community.anovaculinary.com/t/prime-rib-roast/24261/8 "2019-12-24T03:36:34Z")
Thanks.