PedroG

I'm almost positive it's a galvanic interaction (n.b. I'm a mechanical engineer). I've tried insulating it, I've tried leaving the stainless rack out so it's only aluminum, but no dice. Agreed with other people saying it might depend on hard water, but I've lived in four different places with this and it's happened at all of them. When you google "aluminum corrosion in water" you may find some valuable info, e.g. in a brochure of The Aluminum Association which says "Potable water can contain significant amounts of chlorides. Chlorides can be corrosive to any metal if left stationary", or "Fundamentals of Metallic Corrosion in Fresh Water" says "Aluminum holds up well when exposed to air, thanks to a continuous and highly adherent oxide layer, but is generally unsatisfactory in fresh water environments", so you better drain and dry your SVS Demi after each usage, and for 72h-cooking you might consider a different SV rig.

See wiki.egullet.org/index.php?title=Reference_thermometer and wiki.egullet.org/index.php?title=Sous_vide#Thermometers_and_their_calibration. Instead of buying an expensive NIST or ISO calibated reference thermometer, one may just opt for the SousVideMagic 1500D which comes factory-calibrated to 0.1°C accuracy, then compare it with any thermometer with 0.1° resolution and repeat this comparison every few weeks to make sure the sensor is not drifting, and also compare with the spare sensor that comes with the 1500D. I don't know if any other manufacturers of SV equipment do calibrate their appliances, but as has been posted by several members, there are equipments that are significantly miscalibrated.

One thing you might try is insulating (in the electrical sense) the aluminium from the steel. You may be getting galvanic interactions causing the aluminium to corrode. Perhaps some silicon sheet between the two would help. Disclaimer: Only a theory, I haven't looked up the potentials involved and I don't know the unit to understand if this would be possible. You might omit the SS rack, place glass beads or marbles in the bottom of the bag to avoid floating and eventually suspend the bag on a skewer (you may have to cut two notches in the cover to allow for the skewer).

See wiki.egullet.org/index.php?title=Reference_thermometer and wiki.egullet.org/index.php?title=Sous_vide#Thermometers_and_their_calibration.

Be aware that not all fire extinguishers are suitable for a fat burn, see (start at 1:33). A fire blanket is safer.

Merkinz: here are two sources about muscle fibers and collagen shrinking at/above 60°C: Douglas Baldwin's guide "Effects of Heat on Meat" and McGee On Food and Cooking (2004) page 152.

Above 60°C the thin collagen sheaths surrounding the muscle fibers shrink and squeeze the juice out of the muscle fibers, making them dry and tough. Try 48h/55°C-58°C (eventually 72h, but longer cooking time increases liquid loss, you have to find your compromise between juicy and tender).

Thanks a lot, Douglas! You are at cyberspeed!

Wanted: Egg cooking table for 80°C water bath Bob's "Asparagus sunrise" seems to be a nice way to present Onsen Tamago. Here's another way of serving "perfect eggs" with a gelled white: Spinach is cooked with sauteed onions, finely chopped dried tomatoes and pignolias. Four eggs of 138mm circumference from the fridge were placed in a ziploc bag suspended on a skewer and immersed in a 75°C water bath with forced circulation (FMM), pushing the zip under water to allow just enough water to enter the bag to displace the air. After 15 minutes, the bag with the eggs was placed in a pot with cold water to stop further cooking until the spinach was plated, then the eggs were cracked sideways on the counter and easily slided onto the spinach. For me, the eggs were perfect; SWAMBO would like the whites set a bit more, but not rubbery. Maybe this could be achieved by cooking in 80°C water instead of 75°C? Unfortunately I am not a proud owner of an iPhone. Maybe someone with an iPhone could use Vengroff's app to publish a table like Douglas' table but for an 80°C water bath? I guess a few other Windows-bound guys like me would be deeply grateful. Thanks in advance!

That's actualy an excellent idea though the cooking time should adjusted Heat the sausages to 75°C before filling into the cavity!

Instead of filling the pig's cavity with water, why not fill it with sausages like Heston Blumenthal's Trojan hog? BTW there are large plastic bags for storing and compressing e.g. textiles, which have a valve and can be evacuated with a vacuum-cleaner.

Ranz, It's better to cook the cut to be well-done for 45h/55°C (or 57°C) first so the fine collagen sheaths that surround the muscle fibers are gelatinized and can no longer shrink and squeeze the juices out when you transfer the cut to a pot on the stove top or in the oven with water of 65-70°C for e.g. 3h (or for the necessary time according to Douglas' tables). After cook/chill you have to reheat for the time according to Douglas' tables depending on thickness to reach core temperature. The short searing to get a nice Maillard crust will never heat the center of the cut sufficiently. Marinade can be omitted (although it would help tenderizing for a few days in the fridge). When you buy a vac machine (edge sealer) be sure it has an instant seal button and a side port for vacuum containers which will facilitate bagging liquids.

Starting SV for guests with LTLT cooking tough meat may be a bit risky without trying before. Short ribs may have some fasciae that will not be gelatinized enzymatically at 55-59°C. In my experience I have the highest hit rate with racks of lamb. Try to get small ones (about 250g) one per person, or cuts of 400-450g per two persons; larger ones may be from older animals and tougher. Have your butcher vacuum seal them with some dry rub or marinade, or just place them in ziploc bags (see the submersion air displacement method in Douglas Baldwin's guide). SV 55°C for the time according to Douglas' tables. Dab dry and sear the whole eight-bone-racks in almost smoking hot oil (rice bran oil has a high smoking point near 250°C) on three sides, 30 sec per side, cut the racks into two-bone-chops (be aware of the anatomy, the cut is a bit zigzag between the bones) and sear the cut surfaces 30 sec per surface, make it maybe 5 min for the well-done-eaters, or sear one-bone-chops for them. Serve with salt and pepper. Guaranteed fork-tender and succulent. For six eaters you might make two servings to avoid the struggle of searing twentyfour two-bone chops at a time. Happy gnawing!

Comparing 16'/75°C eggs and 50'/64°C+3'/100°C eggs I preferred the 16’/75°C (delta-T method) with its uniform soft gelled white, which is also easier to get out of the shell, just cracking sideways on the counter and sliding out, whereas the 50’/64°C-chill-boil with its overcooked cortex stuck to the shell, it had to be broken and spooned out. Another advantage of the delta-T method: it's faster and simpler, and if anyone desires a second helping, you can serve him or her within a quarter of an hour.

Wattage of the heating element is not that important, steady state consumption is way way lower, see a post in the old SV topic: Heat loss and steady state energy consumption of sous vide cookers. Extremely good insulation may make PID tuning more difficult (less heat loss to counteract overshoot). Low wattage makes ramping up slower, but you can start with hot water. With a 1500W heating element you can stabilize a 130L bath tub to 55°C easily, see "cooking a suckling pig sous vide in a bath tub" (just for fun!).

See "Cooking eggs" in the wikiGullet and the topic "All about sous vide eggs". In Onsen eggs (63°C/45') you will always have a runny white which is often discarded. With the delta-T method (e.g. 75°C/16' for eggs with 142mm circumference) you get a nice set yet soft white.

I did pork tenderloin many times, temperatures from 49°C to 53°C all resulted fine. Searing the whole tenderloin in smoking hot rice bran oil (near 250°C) on all sides for a total of 1.5min to 3min gave a nice crust and an overcooked rim of 1-3mm. Bagging with some marinade or dry rub and dabbing dry before searing facilitates the Maillard reaction. In one instance I cut the whole tenderloin into four pieces before searing, but never into thin steaks! Maybe 52°C is not suitable for your mother-in-law, but definitely worth trying for yourself.

Chris, can you provide some further information on that issue? In my experience, when you smoke something and then cook it sous vide after (typically for 2-3 days), the smoke flavor changes significantly. I'm not sure I have the appropriate vocabulary to describe the change in significant detail, but some of the smoke compounds will actually migrate out of the product through the bag, so you lose those. In addition, the smoke flavor becomes perfectly evenly distributed within the product, which I think leads to a perceived change in flavor as well. It's not clear to me if these are the only things going on, but food that is smoked and then cooked LTLT does not taste like something that is cooked in the reverse order, or in something that is simply smoked up to the desired temp and served. cf. blackp's blind test: Nobody liked the smoke first and then cook SV batch.

The software bug (Output Limit not working below 60%) in SVM 1500D ver. 4.0, 5.0 and 6.0 has been corrected in version 6.1 and later.

I corrected your second link, now it works.

A rationale for cooking poultry at 62-63°C rather than 60°C may be that at 60°C pasteurization times (Douglas Baldwin's table 4.1) are longer than heating times (Douglas Baldwin's table 2.2), whereas they are about equal at 62-63°C, keeping SV time as short as possible. My very most succulent chicken breasts were the ones I had injected ("larded") with coconut oil.

See the sous vide index and the sous vide page in wikiGullet. In my experience 55-56°C / 48h is fine for most tough cuts like brisket or short ribs.

Hi Chris, in the name of all members interested in sous vide cooking, I express our deepest gratitude for the tremendous work you invested in the sous vide megatopic index. We thought it would have been a twelve members' job, but you did it better than any of us could have done. Thank you, thank you, thank you! Regards Pedro

I agree. Rack of lamb is one of my favorite cuts. 3-4h/55°C according to thickness, searing the whole 8-bone-rack in smoking hot rice bran oil, then cutting into 2-bone-chops and searing the cutting surfaces. Cuts of less than about 450g are best, heavier cuts may be from older animals and slightly less tender.

Cracked eggs and messed up SV rig Expansion of the air bubble is not the reason that makes eggs crack. Air is a poor heat conductor and will heat and expand slowly, increasing pressure slowly by about 25% while heating from 5°C (278K) to 75°C (348K); remember Amonton's law aka 2nd Gay-Lussac's law. Cracks happen shortly after immersing the egg in hot water, not at the end of the cooking time. Egg shells may sometimes have uneven thickness, so the thinner parts will heat and expand faster than the thicker ones, leading to tension cracks. Pricking the blunt end of the egg may lead to microscopic relaxing cracks thus avoiding macroscopic tension cracks. Should you need to clean a messed up SV rig, the "professional grill-cleaning-solution containing sodium hydroxide" I mentioned upthread is "Johnson Diversey D9 SUMA Grill heavy duty oven cleaner"; the link has been removed because it was no longer valid. Anyway, preventing a mess by bagging the eggs is easier than cleaning, and suspending the bag makes retrieval easier.