Over Cooking.

Can you over cook food, doing duck breast for dinner party this week, the first breasts I did where Sous Vide for 2 hours. Although pink, they seemed slightly tough to cut, if I cooked them longer, would they over cook, or be more tender.
Any advice please.

Anyone can overcook food Wigan. It happens all the time, but it is more difficult to do using the sous vide technique.

As you gain cooking experience you will learn it’s a product dependant matter of appropriate time and temperature. That’s why recipes from a reliable source can be a good guide to your success. Don’t guess. Food items vary significantly in those two important factors.

I presume you are cooking farm-raised duck. Wild duck is significantly different requiring a longer cooking time, and needs you to remove all the shot.

Two hours should have been sufficient at most reasonable temperatures. However your secret cooking temperature might have been too low if the meat was pink and tough after two hours.

You write, “slightly tough to cut”. Was that acceptable, or unacceptable? There’s many details to consider.
Are you using a properly sharpened knife?
Is your judgement made in comparison to other duck breasts you have cooked using the same technique?
Was it also tough to chew?
A duck’s breast meat is naturally more solid than a chicken’s, if chicken is your basis of comparison. That’s why restaurants frequently slice duck breasts across the grain for service. I would never serve a solid piece of duck breast.

Generally, any meat cooked longer below 145F will become progressively more tender until it is rendered unappetizingly soft. In my experience about 4 hours cooking time would be the outer limit for duck breasts cooked from 130F to 140F.

Wigan, next time you plan to SV cook an unfamiliar meat item try experimenting well in advance using 4 separately packaged half-portions, all about the same size. Start cooking them at the recommended temperature and remove them at one hour intervals. Mark each package with its respective cooking time. Ice bath chill them immediately. When finished you can then compare the resulting degrees of doneness and texture. That will provide you with a guide for the rest of your life for that item. For small or thin items, half hour intervals would be more useful after an initial 45 minute cook. For seafood use even shorter times, like 10 minutes. The outcome of your practical research will result in your personally proven cooking guide. Be patient.

Many thanks for your in depth views, most helpful, and appreciated.