Expert: Chef Glen L. Davis II - 12/19/2008

Question
I would like to know how large of a pork loin roast I need for six people (ribs and weight).  Also, I would like to know what temperature to roast it at, approximately how long it will take, and at what temperature I should remove it from the oven, taking into consideration that I will let it rest before slicing and serving.  What should the temperature be when I slice and serve it?  Thank you.

Answer
It would be my pleasure to answer a question, or rather a series of questions, that is so well asked! Thank you for giving me a clear and concise picture of what you need to know!

First off, for catering events and my culinary school training, I have learned that most people (in a formal 'catered' setting) will eat roughly 8-10oz each. However, my personal experience, between my mothers, grandmothers and my own kitchen tells me that if the people being served are in a comfortable setting (such as a family event) they tend to eat more. My family has NEVER been accused of being "light eaters", we are of viking stock and I usually serve my family about 12-15oz each. With the "sociological" aspect out of the way, I would recommend for a group of 6 average eaters, about 10oz each. For a "bone-in" pork LOIN roast (AKA: pork 'crown' roast, 'Frenched' pork loin, 'royal' pork roast) I would recommend getting one that is about a 5lbs. This amount takes into account the fact that the bones cannot be "eaten" (I did not say it can't be used), and there should be a "fat cap" on the outside surface of the muscle, some people will "trim" it off before eating the meat (personally that is my favorite part!). I have accounted for about a 30% "loss" in the total weight of the roast. This should also allow enough "room for error" in the individual eating habits (i.e. one person might want 8oz of meat another 10-12oz). This should also give you a large enough roast to look for, so that each person will get a "bone", or "chop". You will probably only (from my experience) be able to find a "bone-in" pork loin roast with 7-8 bones or 4-5 bones (depending on the size of the hog) in this weight range. What I recommend, is that you go to the store (best place is a real butcher shop) where you buy your groceries and speak to the "BUTCHER" (your best bet is to go to a REAL butcher and ask them) and request that they "custom cut" your roast, this should be available at no additional or VERY nominal charge.

Some grocery stores have REAL BUTCHERS, that are very skilled and knowledgeable, I recommend Wegman's or Whole Foods, if you are going to try a grocery store. While there are some grocery stores that have skilled personnel, such is not often the case, unfortunately. The best way that I know of to figure out if they are a TRUE BUTCHER is to ask this question:
WHAT IS A CAPON?
The answer is (kind of gruesome, but by no means common knowledge):
A CASTRATED ROOSTER, THEY CASTRATE THEM TO MAKE THEM GROW BIGGER, THEY ALSO HAVE A SLIGHTLY STRONGER FLAVOR THAN A COMMON COMMERCIAL CHICKEN.
If they give you an answer AT LEAST close to that, they know their stuff. I would simply tell them "I saw a re-run of Julia Child's cooking show and she used an ingredient I have never heard of, a CAPON, can you explain what that is to me?", I know it sounds kind of shady, but its your food and you want it to be right! Another question would be "What kind of knives you use o cut the meat with?" or "How do you sharpen your knives to make all these beautiful cuts?"
For the first one, listen for the "key word" CEMETAR (its the 'sword like' knife used on large cuts, it has a curved blade and is the butchers FAVORITE KNIFE!), for the second question if they don't answer "wet stone", "oil stone", "progressive coarseness sharpener", "contractor that comes and sharpens them" or "grinder" (hand grinder and diamond stone are good to!), then they probably are not passionate about cutting meat (I know it sound odd I hear it all the time) or they are not properly trained. The "best bet" is to speak to the "meat department" manager directly and only ask him/her the questions. If they are good butchers they will be ecstatic that they have a customer who knows what they want and who appreciates the quality that they produce. I know that ALL the REAL/TRUE BUTCHERS I know and myself do!
I think that just about covers that topic..... ON TO THE NEXT! I LOVE THIS STUFF!

The next part is what I like to call a "gray area". If you ask someone who is outside of the culinary field whom has heard of a condition called "trichinosis", they will tell you to cook the pork until it is WELL WELL done. This was true to an extent, when our nations supply of pork consisted of "slop fed" and "wallowing" hogs, they (for reasons I will not get into wile discussing food) were prone to "pick up", bacteria and parasites. These days however, our pork is raised and "processed" in "clean farms". What this boils down to is that the hogs have a "cleaner" and healthier diets, and cleaner stalls (concrete instead of mud and "other stuff"). This has almost completely eliminated the risk of "trichinosis". The only case of said ailment I have heard of in recent years, came from someone who ate raw bear meat. Which brings me to the temperature issue.

Personally, I will not (happily) eat pork cooked more than "MEDIUM" (about 145F). I start the roast at least at 425F, for about 12-15 minutes (after seasoning, I like KOSHER/SEA salt, FRESH CRACKED mixed peppercorns, and GRANULATED 'NOT POWDERED' garlic). After the "fat cap" has obtained a LIGHT golden color (should only be slightly golden an starting to form a "crust"), I reduce the temperature to around 325F. I like to let the roast cook at 325F for about 30-35 minutes. After that time has elapsed, check the temperature with an "instant read & heat resistant" thermometer. The reason for a "heat resistant" thermometer is because I do not like to "poke" a hole into the roast and then leave it to "leak" all the delicious juices from, so I leave it in. If the roast is not 135F let it cook for about 5 minutes per 4 degrees shy of 135F. Make sure to check the roast about every 10 minutes. DO NOT let the roast go more than 12-13 minutes without checking the temperature. If the roast is only about 10F off, check it every 5 minutes.  The time it will take to cook the roast will depend on so many factors, that there is no "set in stone" time for cooking. However, for a 5-6lb roast, it SHOULD not take more than 1 hour 15 minutes.

After the roast has reached 135F (a "buffer" of 3-4F is ok), allow it to "rest" (as you mentioned), for about 10-15 minutes. The roast should increase in (internal) temperature by about 12-15F. This should give you a nice SLIGHT PINK center. If you are not comfortable with the pork being served that "rare", the temperature to "shoot for" is about 145F. Cooking the roast to "MEDIUM" will give you the most tender, juicy and delicious meat, compared to the other higher temperatures (i.e. well, medium-well). Another couple ideas that will even further improve the flavor and texture, you need to talk to your BUTCHER a little more. Ask the butcher if they have a "JACCARD", it is a "mechanical" tenderizer that literally cuts into the muscle fibers of the roast with several, tiny sharp knives. This is the same method that many of the best steakhouses use to tenderize their chicken, beef and yes, pork. The may tell you that they cannot do the "JACCARD" because of the bones, if you "sweet talk" them a little they might do it anyways. A little tip, compliment the skill of their cuts and pick an example in the case. One "smooth" line I use is:
YOU MUST BE VERY SKILLED AT YOUR TRADE TO BE ABLE TO GET SUCH STRAIGHT, CLEAN CUTS!
That one works about 95% of the time. Another one is:
I KNOW IT IS A PAIN, AND I DON'T WANT TO BOTHER YOU WHEN I KNOW YOU PROBABLY HAVE MANY OTHER THINGS TO DO, BUT I JUST WANT MY FAMILY TO HAVE THE BEST EXPERIENCE POSSIBLE WHEN EATING THE ROAST. ITS FOR A SPECIAL DINNER AND I WANT THEM TO APPRECIATE YOUR CRAFT AS MUCH AS I DO!
That one has about a 98% chance, and trust me it is worth it!
I actually got almost everyone I know a hand-held "JACCARD" tool for Christmas.

I know you didn't ask for advice on sauces but I have to share one of my absolute favorites with you! I served this in a few of the restaurants that I worked in, it sounds kind of odd, but it pairs AMAZINGLY WELL with pork loin/tenderloin roast!
Here is the recipe (keep it secret many people cant figure it out):
1 cup dessert wine (I like a 'cheap' Muscat)
1/2 cup strawberry/raspberry preserves (with the seeds strained out)
1/2 cup RAW SUGAR (needed for the "molasses" taste)
1/4 tsp KOSHER?SEA salt
1/8 tsp FRESH CRACKED BLACK PEPPER (or mixed peppercorns)
-Combine all the ingredients in a medium "sauce pot", stir to mix. Heat the sauce over a medium heat, stirring OFTEN (not constantly), until it reaches a boil (if you are not watching it can boil over), after a boil is reached, reduce the heat to maintain a simmer, keep simmering until the sauce reduces by about 1/3-1/2. use as a "garnish" sauce or place it on the table (if dining "family style") for each person to put their own sauce to their taste.
This sauce plays on the subtle natural sweetness of the pork. It is also PHENOMENAL on ice cream, fresh fruit, pound-cake or as a "mixer" for almost any "cocktail" that calls for "grenadine".

Well, I think that about does it! Sorry to give you so much information, I get carried away sometimes (when I like the question)! Please let me know if I can be of further assistance, clarification or more questions! Please keep them coming!   
GOOD LUCK, HAPPY COOKING, HAPPY EATING most of all MERRY CHRISTMAS!