Dyes

Thinking Outside of the Vacuum Seal Bag – What else can the DSV do?

While the Dorkfood DSV was originally designed and made with just sous vide in mind, we have discovered that a temperature controller such as ours can be useful in many other applications as well.  Our Dorkfood family has used their brains and creativity to pair the DSV with projects from other kinds of food prep techniques to brewing, and even home crafts like creating clothing dyes.

Bain Marie

Bain-MarieBecause the DSV is in essence, just a highly sophisticated temperature controller, its main use has been in sous vide cooking.  But since there is not actual heating element or tub attached to the device, it can really power anything that needs to heat up and maintain a temperature under 200˚ F.  This includes an electric pot or hotplate used in a bain marie set up.  

In layman’s terms, bain marie is really just a fancy name for a double boiler system.  We have enterprising Dorks that have applied the DSV to this set up instead of sous vide and have made some amazing custards, sugar and chocolate confections and many other mouth watering concoctions.  Since the DSV maintains the bottom water bath at a precise temperature, this double boiler method is much more accurate than simply heating on the stove.  

Yogurt

We have many Dorks that use their DSV to make homemade yogurt.  This saves on money and allows for creativity and personal taste choices to flourish.  Our Dorkfood family members have reported making their homemade yogurt in one of two ways – in glass jars and straight in the tub where water would normally go for a sous vide application.  

Both methods work well and allow the yogurt to mature at a constant and controlled rate.  Recipes for various yogurts abound, but the most common is to slowly heat the yogurt at around 110˚ F – 120˚ F from 8 – 12 hours our so.  Once this is done, you have yourself some very yummy homemade yogurt of your choice of flavors and type.

Home Brewing

Home BrewingAnother way in which our DSVs are used in non-sous vide roles is with home brewing. Taste and quality of our alcohol has become more important with the craft beer cultural revolution.  And, right along with that is the upsurge in popularity of home brewing the perfect beer.  In some of these home brew recipes, a step is added called the mash process.
In this step, the brewer basically steeps the grain mixture in hot water to hydrate the barley, activate the malt enzymes, and convert the grain starches into fermentable sugars.

Since the mash should never reach past 170˚ F, the DSV is ideal for heating and maintaining a temperature in the hot water and grains that allow all of the reactions to take place that are needed for these beers.  And, while the unit cannot help in the slow cool-down phase of brewing, many or our Dorks have found that precisely controlling the mash temperature is a big plus.

Clothing Dye

One of the applications that we learned about from our Dorkfood family is the making of clothing dyes.  People have been making dyes since times of old and we are rediscovering this lost art.  Many or our Dorks have found the benefits of making their own clothing dyes at home range from money saving to health based.  Making your own dyes means you know exactly what is in them and also means you need not pay the store a lot of money for a tiny bottle.

Dyes can be made from any number of things including berries, dark veggies, minerals, etc.  Basically anything natural that has its own pigment can be used to dye cloth.  Our Dorks make their dyes using these ingredients mixed with hot water.  This hot water mixture then steeps anywhere from a few hours to over night, depending on the preferred deepness and strength of the dye.  Here again, the DSV lends itself nicely to helping control and maintain the precise temperature for the dyes to reach perfection.

Conclusion

These are but a few of the examples of ways that we, and our extended Dorky family, use precise controlled temperatures and the DSV in ways that Dorkfood originally never even thought about.  We get questions and comments often about ways in which people might apply the DSV to their creative thinking projects and come up with amazing ways of heating DIY hot tubs or make clotted cream or soup.  What do you use your DSV for?  We love to hear about the new and interesting ways our extended family members are getting Dorky and thinking outside of the vacuum seal bag!

Christmas Tree

12 Foods of Christmas from Around the World!

With so many people and Dorks celebrating Christmas in one form or another around the world, we thought it would be fun to take a look at some traditional Christmas foods (and maybe how they can be cooked sous vide, because of course).  In many cultures, Christmas is more than just one day of present giving and worshipping.  It almost always involves family, fun and great food traditions.  Here are but twelve examples that we have found that represent global traditions.

Mediterranean

Malta

Imbuljuta Tal-Qastan – This delicious holiday drink from Malta melds chestnuts and hot chocolate.  What’s not to love?  Traditionally, it takes a day or two to make simply because of having to soak the chestnuts over night in order to remove the shell pieces and lining.  Then, the chestnuts are boiled in water with sugar, cocoa, and tangerine rind until the nuts are tender and the drink is piping hot.  This usually takes a few hours as well.  An enterprising Dork might try this sous vide by adding all the ingredients (including the cleaned chestnuts) into a vacuum bag, setting the water bath to about 160˚ F and letting it soak for about 15 hours.  This will take longer than the original recipe, but just imagine the intensity of flavor using this sous vide setup would pack into a cupful of this Holiday delight?

Avgolemono Soup – A delicious tangy chicken soup that is a holiday favorite in Greece.  This soup can be made quickly or slowly, depending on the depth of flavor and ingredients you choose.  The main ingredients include chicken, lemon juice, eggs, and rice or orzo.   For the sous vide twist, we recommend setting your water bath to 150˚ F and soaking your chicken with olive oil, chicken broth, flavor veggies, salt and pepper for about 5-6 hours.  Remove the chicken from the vacuum and set aside to cool.  Strain the cooking liquid and use in a pot for the soup.  Shred the chicken and add it and mostly cooked rice or orzo to the soup liquid.  In a separate bowl, whisk together eggs and lemon juice.  Here is where the tricky part comes in.  You must temper the eggs so you don’t end up with egg drop soup.  Slowly whisk in the egg mixture into your soup and heat, but do not allow to boil.  The extra effort is worth it for this smooth holiday treat.

African

Doro Wat – A staple in Ethiopia, this dish is also a holiday must.  In essence, it is a savory chicken stew eaten traditionally with injera bread.  Since this is a stew and it is a long cook to begin with, sous vide techniques are not a big stretch. Caramelized onions, kibbeh spiced butter, cubed chicken thighs, salt, lemon juice, spices, wine and honey go into a vacuum bag for about 5 hours at 150˚ F.  Hard-boiled eggs get added about half an hour before serving.  This dish serves up deep flavors of Africa for Christmas dinner.

Akoho Sy Voanio – This Christmas dish hails from Madagascar and other parts of Africa.  It is a coconut chicken soup usually served over rice.  This is a relatively easy recipe that involves combining coconut milk, chicken, onions, tomatoes, garlic, ginger, salt and pepper into a delicious soup.  This can be done with sous vide methods with a water bath soak for about 3 to 4 hours at 148˚ F.  The coconut flavors mix with the ginger and garlic to elevate this beautiful chicken soup, which would be perfect for a cold winter’s night.

Asian

Asian ChristmasBibingka – A rice flour coconut cake from the Philippines starts us off in Asia.  This traditional cake brings the flavors of the islands into a traditional Christmas meal.  While baking with sous vide is generally not done, this treat was too good to pass up for the folks at Sous Vide Supreme who have an excellent step-by-step recipe for this holiday favorite. 

Fried Chicken – In Japan, Christmas is traditionally celebrated with fried chicken, because why not?  Often times, in Japan this traditional meal is made by a certain fast food chain hailing from Kentucky.  But, why buy that when you can make it yourself and it tastes so much better?  Obviously, one cannot deep fry in a sous vide set up.  However, that doesn’t mean you can’t sous vide your chicken with some spices beforehand at around 140˚ F for 2 to 3 hours to really bring out the flavor before breading and dunking those bad boys in some hot oil.

European

Ciorba de perisoare – This Romanian meatball and veggie soup is a Christmas tradition and a delicious meal to warm you up when it is cold outside.  The basics of this dish are meatballs of your choice of meat, broth, onions and other veggies like cabbage celery and carrots.  This soup also makes good use of lemon juice.  In order to sous vide this dish, we would recommend a cook time that agrees with whichever meat you chose.  This means longer cook times for beef and pork and shorter ones for chicken or other poultry.  Because they are meatballs and not cuts of meat, the cook times won’t be that terribly long – maybe somewhere between 2 to 3 hours.  The water bath temperature should also be adjusted for the meat being cooked.  Using sous vide methods will bring out the flavors of the meatballs while marrying beautifully with the vegetables and broth.

Pavo Trufado de Navidad – A stuffed turkey dish with a twist from Spain, this delicacy includes the tasty poultry stuffed with truffles.  Yup!  Those delicious and often expensive fungi that fancy restaurants shave over everything get stuffed in turkey for Christmas dinner in Spain and it is amazing.  In order to make this Dorky, one could sous vide the turkey with spices and a bit of truffle ahead of time before taking it out, rolling the truffle stuffing inside and baking until golden and delicious.  This would elevate not only the turkey flavors but infuse everything with even more truffle goodness.

South American

Vitel Toné – This dish hails from Argentina but was heavily influenced by the Italian immigrants who moved there and brought with them Christmas traditions.  Veal, tuna and capers combine and in unlikely but remarkably tasty dish that mixes the flavors of Argentina and traditions of Italy.  To really get the tastes of this meal, we suggest browning the veal before giving it a soak in a sous vide water bath until it reaches a core temperature of 131˚ F.  Once that is done, add the tuna sauce made with eggs or mayonnaise (depending on the amount of oil you prefer) and vegetables to your veal and top with capers.  Simple, delicious and perfectly mixing of cultures and traditions for Christmas.

Hallacas – Venezeula’s answer to tamales and oh so delicious, this Christmas treat combines corn dough and vegetable and meat stew.  The meat stew can be made ahead of time and of course we recommend sous vide for the best flavor possible.  Then you make your corn dough, flatten balls of it on oiled plantain leaves, spread some of your stew on that, fold it up and tie with twine.  It then gets boiled for about twenty minutes.  This hearty meal is perfect for Christmas.

North American

Chiles en Nogada – This beautiful dish comes from Mexico and looks like a Christmas card.  It involves a poblano pepper stuffed with your choice of meat, covered in a walnut sauce and topped with pomegranate seeds.  Cook your stuffing with herbs and spices ahead using sous vide methods with temperatures based on whichever meat you choose.  Then stuff your pepper and bake.  Top with the signature walnut sauce, pomegranate seeds and green herbs to have a festive Mexican Christmas dish.

Christmas Ham – Let’s finish our tour of the world in the USA where many enjoy ham on Christmas.  Usually these are coated with a sugary crust or syrup, bringing out the natural sweetness of the pork.  While sous vide-ing an entire ham may be a bit daunting, one can get smaller cuts to soak in a water bath for hours with oils and spices.  Once it is done in the bath, a sugary crust can be applied and the ham put in the oven to crisp.  Delicious and traditional for many celebrating this time of year.

 

5 gallon bucket

Large Sous Vide Water Bath Setups

We’ve discussed smaller water baths previously, so for this post let’s switch focus to the big baths that can handle some serious meals. These are the slightly unconventional, but incredibly useful, sous vide setups that allow for making larger meals, multiple recipes, or feasts to feed the masses. Some of our Dorkfood family members have even made things like suckling pig or full racks of ribs using these baths.

Some of the commonly used bath appliances we covered under a previous post do come in larger sizes, but here we are talking about the really big baths. There are a few general ways in which these can be made, but two of the more common are using 5 gallon buckets and insulated coolers. These larger cooking vessels often take a bit of ingenuity, as they don’t come with built-in heating elements. Many Dorks have had success pairing immersion heaters, usually used for aquariums (like the Finnex), with the DSV for heating their large water baths.

5 Gallon Buckets

5 gallon bucketThese large buckets are popular with home brewers and readily available in stores and online. The buckets are simply large containers, so an immersion heater will come in handy for heating this bath up to the desired temperature. Because of the amount of water, this and any other large bath will take longer to heat up to temperature than the smaller versions.

The size of the bucket, while ideal for holding all that water, may not be great at evenly distributing the heat. Indeed, due to the size and the sheer amount of water, you may find that hot and cold spots form in the water bath. As mentioned with the larger of the more common appliances, an easy test for this is to give your water bath a stir – if the temperature changes by more than a degree, circulation should be introduced. This will help keep your temperature consistent and your food evenly and safely cooked.

One important thing to note here is to keep the probe away from direct contact with the heating element. The heater may get far hotter than the water around it and the probe is not guaranteed past 200˚ F.

Insulated Cooler

Sous Vide Setup with insulated cooler

While these containers can come in smaller sizes, large insulated coolers can be made into ideal sous vide water baths for extremely large meals. Not only can the large insulated coolers hold a lot of water, they have built in heat/cold distribution. Essentially, when a Dork hooks up a heating element to the DSV and lets the water bath come to temperature, the insulated cooler will maintain that temperature with far less effort on the part of the DSV and the heater. This means less power cycling and leads to a savings in energy.

Just this past year in Arkansas, Dorkfood was honored to sponsor a tent at the Camden Daffodil Festival’s Championship Steak Cookoff in partnership with the folks at Let’s Talk BBQ. We used the insulated cooler method of cooking sous vide to serve up over 100 perfectly cooked steaks to a hungry Cookoff crowd. The steaks and the fair were a huge hit and showed off the greatness of combining meat, sous vide, and the DSV.

Learn more about the Dorkfood DSV, or tell us about your own sous vide setup in the comments.

 

 

turkey

Happy Thanksgiving!

We all have different traditions and family favorite foods for this holiday.  Here at Dorkfood, we thought exploring some of those traditions and our own favorites would be a great way to get into the Thanksgiving mindset.  

Turkey


turkeyOn almost all of our tables, turkey is the star of show.  And while it is undeniably delicious, why is turkey our Thanksgiving meal of choice?  Elementary school folklore would have us believe that the Pilgrims ate many of the same foods we eat today, including turkey, at the First Thanksgiving.  Historians say, however, that turkey may not have been on the menu at all.  According to colonialist Edward Winslow’s journal, the only mention of turkey around the time of the First Thanksgiving in 1621 is an entry detailing how he had joined a hunting party for the birds a few months prior.  In fact, those meats that are mentioned at that first meal between the Pilgrims and the
Wampanoag people are “wild fowl” (most likely ducks or geese) and venison.


It wasn’t until 1863, when Thanksgiving was declared a national holiday by Abraham Lincoln, that turkey became a staple of the meal.  Historians believe that there were a few reasons that turkey became the meat of choice for the holiday. Turkey had become popular in England high society, and therefore eating turkey was fashionable for a celebration.  Another reason was the popularity of A Christmas Carol, in which Scrooge gives out Christmas turkeys as a sign of his changed heart.

Whatever the reason for its initial popularity, the turkey now takes center stage at most Thanksgiving tables.  So, whether your turkey cooking tradition is roasting for hours and hours with stuffing, spatchcocking the bird with herbs for more even doneness, or deep frying (please, for the love of your house, do this outdoors), gorging on turkey and slipping into tryptophan bliss this Thursday sounds pretty great indeed. But a delicious bird does not a Thanksgiving dinner make. Let’s look at the supporting cast.

Mashed Potatoes and Sweet Potato Casserole

These two tuber dishes are now a staple of almost every Thanksgiving meal and often rival the turkey in their popularity.  And, like the turkey, neither of these dishes were served at that First Thanksgiving meal.  The Pilgrims and Wampanoag would not have had potatoes in 1621.  They may have had other root vegetables to tide them over, but the potato and sweet potato were not introduced to the North American diet until later.

As for our modern potato dishes, the historical use of these tubers can generally be split into northern and southern traditions.  The white mashed potatoes we know today more than likely started in the northern states while sweet potato and yam casseroles came from the south.  

We here at Dorkfood have our own family traditions.  Some of our Dorks make those smooth, delicious mashed potatoes with fat drippings from the turkey and a bit of margarine, instead of milk and butter, to adhere to Koshrut laws about not mixing milk and meat.  The results are delicious because the turkey drippings add a nice bit of fat and flavor to the potatoes.

Other Dorks have had the southern traditions of sweet potato casserole passed down through the generations.  These casseroles certainly vary from recipe to recipe, but the sweet comforts of brown sugar and marshmallow seem to bring back many happy, Dorky memories.

Stuffing (or Dressing)

As far as long-standing traditional foods go, stuffing has been around in one form or another since the Roman times.  The French called it farce until the word “stuffing” finally came onto the scene.  In Victorian England it was decided that the word “stuffing” was not acceptable in polite company and the word “dressing” was substituted.  Nowadays, one generally refers to the stuff that was cooked inside the turkey as “stuffing” and the food that was cooked separately in a pan as “dressing.”  

Most people have their own favorite stuffing recipe and it is usually very similar to whatever was served when they were growing up.  Many have fond memories of Stovetop stuffing with its bread, herbs, stock, celery and onions.  Here at Dorkfood, we have those traditions, as well as a few different takes on an old theme.  Some of our Dorks have discovered that substituting wild rice and chestnuts for the bread makes for a delicious stuffing that is also gluten free.

Another Dorky variation on the stuffing theme is using the Stovetop ingredients, adding sausage, and baking in muffin tins for even and quick cooking.  These “Stuffin’ Muffins” are a fun way to preserve the stuffing heritage while providing equal portions to many hungry mouths.

Pumpkin or Sweet Potato Pie

Let’s finish off our meal with pumpkin pie.  Finally, a dish that’s main ingredient probably was at that First Thanksgiving!  While pumpkins were available, sugar was not. They would not have had quite so easy a time satisfying their sweet tooths.  Since sugar was not readily available to the colonialists, their pumpkins would most likely have been served roasted, maybe with some honey or herbs.

The pumpkin pie as we know it probably sprung up in the mid 1800’s as sugar was more accessible and stove ovens became more popular.  Since then, people have been serving their traditional pies for Thanksgiving.  Some Dorks make use of the canned pumpkins and some go whole gourd and get small pie pumpkins to roast and puree for their traditional meal cappers.

Another dessert custom is the sweet potato pie, again exemplifying the differences between northern and southern traditions.  The northern traditions usually involve the pumpkin pies while the southern traditions embrace the sweet potato again.  The sweet potato pie has many of the same spices, but the flavor is all smooth potato-y goodness.

Whether you demand pumpkin or sweet potato pies (maybe some of each?) for your final bite of Thanksgiving, both desserts offer an orange/brown, spicy, sweet finale to a great meal.

roaster

Popular Appliances to Use with the Dorkfood DSV

Hello Dork family! Welcome to the new Dorkfood Blog. Since we get so many questions from prospective Dorks about what types of appliances can be used in conjunction with the Dorkfood DSV, we thought it would be fitting to focus our first blog entry on those appliances. This information should help get future Dorks up and cooking and, even if you are a current DSV aficionado, maybe this post will fan the flame of that experimental foodie we know is inside every Dork.

Before we delve into those appliances, we have to make sure they will work with the DSV. We have devised a method for testing whether that appliance will work with the DSV called the “plug test:”

  1. Plug your appliance into an ordinary outlet and turn it on until it starts heating.
  2. Unplug it without pressing any switches or changing any settings.
  3. Plug it back in.

If the appliance continues heating after step 3 (without any additional user input), it will work with the DSV.

Types of Appliances

Slow Cooker

Sous-vide cookingWhy don’t we start with the main appliance that the DSV plays well with: the slow cooker. Now, not all slow cookers are made the same and not all slow cookers will work with the DSV. The fancy slow cookers (usually the digital ones) will most likely not pass the “plug test” and therefore, are not compatible to work with the DSV. I have even come across a slow cooker model that uses a manual knob, but requires the user to select one of three different size settings before heating up. This additional step in the process means that this model of slow cooker will also not cooperate with the DSV.

While this sounds limiting, the slow cooker remains one of the best appliance options to use with the DSV for sous vide in the home. A good thing to keep in mind is that those simple knob slow cookers are far less expensive than the pricier digital kind. Another advantage is that slow cookers are made with a ceramic tub that is heated by the metal bowl it sits in. This heating method ensures that heat is distributed evenly through the food, and for our purposes, water bath.

Because of this heat distribution, the fact that the ceramic tub won’t usually get hotter than the temperature you want, and there won’t be random cold or hot spots, it is ideal for the DSV. With the lid on, water loss through evaporation is minimal, and circulation is almost never needed. It really is a simple plug-and-play situation. The home chef can vacuum seal their desired meal, place it in their preheated water bath in the slow cooker (set to high and using the DSV), and let it go for the required amount of time.

Rice Cooker

Anshin_Rice_Cooker_with_Smart_SwitchRick CookerThe rice cooker is another popular appliance for use with the DSV. Again, the stress for these should be on the simple models. Most simple, non-digital models of rice cooker rely on a weight shift mechanism for cooking the rice. This means that you put rice and water in the metal tub and set the lever to “cook.” As the rice cooks it will absorb some of the water and some of the water will be lost to evaporation. Once enough water is gone from the tub, the weight shift kicks in and the rice cooker switches operation from “cook” to “warm.” As a sous vide water bath won’t be absorbed by a grain, and lower temperatures minimize evaporation, your rice cooker should not shift to “warm” during the water bath cook time.

You may run into problems if your rice cooker is a thermostat shift model, so it is always good to conduct that handy “plug test” from above to make sure it will work with the DSV. Do bear in mind that rice cookers have a more powerful heating element. So, while your water bath will heat up faster, it may cause problems where the DSV cord rests on the lip of the water bath tub. A simple solution that many Dorks use is to keep the cord wrapped loosely in aluminum foil at the point of contact with the tub.

Roaster

roasterLet’s move on up to the much more powerful appliance – the roaster. Many of our Dorkfood family members have found that roasters are good for larger amounts of food and will heat up far faster than the slow cookers and rice cookers. Here, again, your preferred appliance must pass that “plug test” in order to work with the DSV. We have found that those roasters with simple dials that indicate either actual temperature or high/low have the best chance of working for you.

Like the rice cooker, the point of contact on the lip of the bath may be a problem spot for the DSV probe cord. Keep in mind the above advice about the foil and just make sure that the cord is not in contact with any of the metal of the water bath. This includes the probe that is inserted into the water. You want to be sure that the probe is not touching the sides or the bottom of your roaster as these are likely to get way hotter than the max of 200˚ F and you may end up with a melted cord, which is no fun for anyone.

Because of the more powerful heating element and the larger water bath, you may find the need to use circulation when cooking sous vide in a roaster. To determine if this is the case, we recommend getting your bath up to temperature and then stirring it – if the temperature changes by more than a degree, the bath will benefit from circulation. In those cases we recommend using an aquarium bubbler – even a small one (“200” series) can introduce enough agitation for sufficient circulation. You can also simply stir the water every now and then to break up those hot and cold spots, but this requires more attention.

Smoker

smokerFinally, we have the smoker. A bunch of Dorks use their DSVs with a smoker for both a sous vide water bath and for “cold smoking” meat and fish, though probably not at the same time. The same rules apply to the smoker as the roaster. Protect your cord on the lip and make sure that the probe doesn’t touch the sides or bottom. And, of course, your smoker must pass that “plug test.” (I promise that is the last time I will mention “plug test” in this post).

“Cold Smoking,” as defined by The National Center for Home Food Preservation, is a process of smoking meat and fish “that is done over a much longer period of time, e.g. 12-24 hours…Since foods are held in the temperature danger zone, rapid microbial growth (40-140°F) could occur. Therefore, only those meat products that have been fermented, salted, or cured, should be cold-smoked. Most cold-smoked products should be cooked to an internal temperature of 160°F before they are eaten. However, not all cold-smoked foods are treated this way, e.g., smoked salmon and cold smoked mackerel, which are very delicately smoked for a long period of time and remain raw even when eaten.” Because of the dangers involved, please be aware of the microorganisms that may latch on to your food and read the guidelines over at the FDA before attempting this.

Conclusion

Those are our big four appliances. Our Dorfood family uses these slow cookers, rice cookers, roasters and smokers to make some amazing meals. Hopefully this list will have inspired Dorkfood Nation to get cooking with their preferred appliance and maybe try out a new appliance they didn’t know they could use.

Happy cooking, everyone!

 

Sous-vide cooking

What is Sous-Vide?

Sous-vide is one of the most precise cooking methods available.  Cooking (in the literal sense) is done to provide flavor, modify texture, and kill microorganisms. Most cooking methods require lots of heat and a little bit of guesswork: if you’ve ever over or under-cooked anything, you can attest to that!

Sous vide is different: you heat the food at the desired final temperature – there’s no guesswork.  For example, if you want to prepare a medium-rare steak (with a center of 130°F) your sous-vide water-bath would be set to 130°F.  The result is extremely consistent, whereby the temperature and ‘doneness’ of the food is exactly the same from the outside to the center – perfect every time.

Sous-vide requires a water-bath with precise temperature control.  Food is placed in the water-bath, typically after being vacuum-sealed (exceptions include eggs or cooking in brine).  Sealing the food allows it to fully retain flavor, moisture and nutrients during cooking, makes for easy cleanup, and allows for painless transfer between fridge (or freezer) and water-bath.

Once purvey of top chefs and restaurants who could afford laboratory grade temperature controllers, sous-vide is finally accessible to the home chef.

Sous-Vide Reference Chart

sous vide reference chart