As per everything, knowing the thickness is half the battle won as to cooking times.
So familiarise yourself with the free online works of Douglas baldwin (link 3)
Useful cooking times link in both c/f
Sous Vide Time and Temperature Guide – Anova Culinary this guide is in the anova app, but is harder to find on the sites footer page thus the inclusion.
If you don’t read this & poison your work colleagues / family do not blame us…
Me I have some mutton in the freezer yet to be dealt with, but would recommend if a uk type steak thickness compared to US (which messes we non US folks up using things like the anova app) then 60c 4
This is based on lamb with a minimum of 1 to 3 hours cook, but extending it for the fact it is mutton & start there for a medium (not my idea of lamb product) …truth be told I’ve looked around a few times for mutton specific & not seen a lot to give me anything definitive, thus if you attempt it make sure to log it all in a notebook & let us know how you got on, it will be very helpful going forward.
But rather than a strangers suggestions not bearing the brunt of a mis-cook, may I recommend you make BURGERS first (mutton burgers are divine as i’m sure you know) follow the burger guide on the app / website & modify once your personal level is dialled in)
Whilst lamb vs mutton is different, as is minced lamb to minced mutton, it is likely the most expedient way to work out how it cooks in a burger patty form for density, despite what a mincer obviously does, & if you have not already attuned yourself to a sous vide burger, they can be sublime (quick too)
However, I will throw this at you, due to not being an expert in the kitchen, but liking a good pan char on my steak (whatever the meat) BUTTER, one steak at a time, tongs to flip & resist the urge to press the steak into the pan, I count based on appearance up to 40 seconds per side come hell or high water I ignore everything going on around me, because it leads to greyed overdone meat.
The other element I ascribe to (new to sous vide or not) is to do the steaks to one stage lower than you want, that way a screw up in the hot pan (is less likely to have you making apologies for overdone meats) …because everyone’s hob is different, my cheapo ikea induction is very “pulsing” making it unfit for caramels (sweets) as it has sod all control but is fine for the basics, so don’t punish yourself, know your kits limitations, practise.
The result in our house at least it that finally my wife who hammers (eats) steak like there is no tomorrow, unlike daughter & myself prefer(red) better done steak, as long as the char is good it turns out she will eat & relish it any way it is presented, so I have been dialling temps back (from cooking two sets of steaks RARE (me & daughter) then faffing to get the wifes done at a modified temp (well vice versa actually as cook the highest temp first then leave it in having added water to lower the (mine & daughters) steaks whilst the wifes sits there in a holding pattern in the same water …hope you see what I did there, as there are only a few degrees difference when we look at the temp scale.
Presumably it is less than a US 1.5 inch thickness? (for some context)
May I ask, supermarket? (if so which)? uk? new zealand australia? …for me mutton is rarer than rocking horse poop in the uk.
But with lamb & mutton less is more, the times & temps can be very controversial as to pasteurisation et al, a google search will throw that up for you. it can be as low as 51c …if you uk google search it throws up a posh chef recipe that presumably is “slivers” of lamb" 10 minutes at 68c & very, very pink (they adjusted it to this temp after too many complaints at a previously much lower temperature)
If the mutton is a generally “unobtainium” then freeze it & do some more research & proffer some practise lamb instead till you have a feel for which way it is going to go.
NB we do have Venison recipes / timings on the site, which obviously are another perceived headache, so if you have the app, go look at the temp guide & work it from there.
I have had zero success with a big long leg of lamb cook" (48 hour type thing) would stick to steaks & small roasts.
Highly recommend (if in the uk) cornish sea salt company (soft crumble, delicate flavour flakes) when prepping for the bag with herbage or without, hard to overdose on it, sprinkle it & let it sit for 30 mins- 50(ish) for penetration before the plunge.
If you are UK, & you have a costco near you, they do good deals on (reusable a few times) bacofoil brand sous vide (to 80c) double seal ziplok bags, the 1 litre (small) is enough for two typical uk steaks, or 6 uk bangers (for some comparison) the 3 litre bags have essentially remained unused in our home as meal size meats are the order of the day, less so joints. very good value & fit for purpose, don’t risk other lookalikes! (they are selling smaller packs more expensive in a few supermarkets now, eg morrisons) superb for the immersion air removal seal at point of plunging!
But now… a proper video suggests a multiday cook understandable & not theoretical, his was heavily dry aged, so make of that what you will for affecting times, a lot of research needed to dial in with certainty imho, as a search always pulls up LAMB not MUTTON
Lets throw the cat amongst the pigeons…