KitchenSavvy

Canning Barbecue Sauce

I have been making my own barbecue sauce.  As of yet I have not been able to make the sauce thick enough.  When I do achieve the right thickness and process bottles in a pressure cooker, the thickener I use breaks down and my sauce is the consistency of water.  Any suggestions on the best thickeners to use?

--Bob

Since you didn't say what you are using as a thickener, I can only speculate that it is a starch of some sort.

Starches are made up of two kinds of molecules; amylose which is a long chain of glucose molecules, and amylopectin which is also made of glucose molecules but with a ramified or branching structure.  In plants, starches are deposited into granules which contain many starch molecules.  While amylose is water soluble, amylopectin is not.

When a solution containing starch is heated, two things happen.  First, the amylose molecules dissolve into the water where, because of their length, they form a tangled mesh which traps the water and any other materials.  At the same time, water infiltrates the starch granules, causing them to swell.  All of this typically happens in the range of somewhere between 120°F (49°C) and  180°F (82°C).

Your problem is that, as the starch-thickened mixture is subjected to prolonged cooking at higher temperatures, the starch granules rupture releasing their trapped water back into the sauce.  Also, some of the starch molecules begin to break down into smaller fragments which are less able to form the mesh which thickens the sauce.  The breakdown of starch molecules is encouraged by the acidity of the sauce.

Unfortunately, there is no good way around this problem, especially for the home cook, other than carefully cooking your barbecue sauce down until it is thick enough without the addition of a thickener.  It should be boiled gently until the volume is reduced by half or until the mixture rounds up on spoon without separating.

A recipe for barbecue sauce suitable for canning developed by the USDA can be found at http://www.uga.edu/nchfp/how/can_03/bbqsauce.html.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

How to Stop Guacamole from Turning Black

I have heard that to stop guacamole from turning black that you should save the avocado pit and put it on top of the guacamole once it is made.  How does this work?

--Marc

This tip works only if the avocado pit is big enough to completely cover the bowl from edge to edge.  What it does is exclude oxygen.  Once the avocado fruit has been cut and the contents mashed, an enzyme released from inside the cells of the avocado flesh starts causing the pulp to turn brown in the presence of oxygen.  Placing the pit on top of the guacamole keeps oxygen away from the area directly in contact with the pit.  The surrounding area not covered by the pit still turns brown.

Any oxygen impermeable barrier will stop browning from happening; an avocado pit, plastic wrap, as Harold McGee found in The Curious Cook: More Kitchen Science and Lore, even a 40 watt light bulb (not recommended).  While McGee found that all plastic wraps worked to some degree, Saran Wrap, which allows less oxygen to pass through it than some other brands, was most effective.  Whatever material is used, it should be pressed gently down onto the surface of the guacamole to remove as much oxygen as possible.

The citric acid in the lime juice used to make guacamole also helps a bit, but to be completely effective it would need to be used in much larger amounts than most recipes call for.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Open Freezing

This summer we had a large crop of raspberries which I froze to use later.  They are now one solid block of ice.  Is there any way I can freeze them so that I can measure out the amount I need rather than having to chip chunks out of a block?

--Joan

You can freeze berries, beans, and other fruits or vegetables using a technique called open freezing to keep them from forming a solid block.  To do this, rinse the fruit or vegetable to remove any dirt or foreign particles.  With some foods like beans, carrots and the like, larger pieces can cut up into mouth-sized bites.  If necessary, blanch the food, and then dry it completely.

Place the food in a single layer one or more cookie sheets which have been lined with parchment paper so that the pieces are not touching. Put the cookie sheets into your freezer and leave them until the food freezes solid.  Depending on the size of the pieces, this can take a couple of hours or more.   Do not, however, leave the food like this for too long as prolonged open exposure to the air in the freezer will cause loss of quality.

Make sure to lay the sheets flat, so that the food doesn't all slide to one end and the pieces touch one another.  Do not stack the cookie sheets one on top of the next as this will delay freezing, and may damage the food.  There should be plenty of air flow over the top of each sheet.

Once the food is frozen, it can be removed from the parchment paper and put into labeled, resealable freezer bags or containers for longer storage.

It is necessary to make sure that the food is completely dry before open freezing or it may stick permanently to the parchment paper.  I prefer parchment paper, however, as its silicon coating reduces the chance of this happening and if something does freeze to it, I don't care if it gets torn.

The University of Missouri Extension branch has a list of vegetables and the blanching method and times to use at this link.  Blanching slows down enzymes that can cause food to lose its color or quality.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Freezing Green Tomatoes

Can green tomatoes be frozen? We love fried green tomatoes and we have a lot of green tomatoes that we hate to throw away. I was wondering if they can be saved by freezing.

--Don

Fresh tomatoes, red or green, can be frozen by simply removing the hard portion at the stem end using a sharp paring knife.  Place the whole tomatoes in a single layer, either on a cookie sheet or in bags, in your freezer.  Freezing them in a single layer will make it easier to remove only as many as you need at a time later.  If you freeze them on a cookie sheet, transfer them to plastic bags for long term storage.

To thaw, place as many as you need into a bowl and leave in the fridge, covered, overnight or defrost them gently in the microwave.  The skins will peel off easily and the tomatoes can be used for any recipe where canned or fresh tomatoes are cooked until soft, such as sauces or stews.

Frozen green tomatoes can likely not be used for making fried green tomatoes, however, as the cell damage from freezing will cause them to release a large amount of water.  In turn, this will cause the breading to come off during cooking.  Also, the tomatoes themselves likely be too mushy.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Tomato Concassé

I have a recipe that asks for "tomato concassé".  What is it and how is it used?

--Julie

Tomato concassé (pronounced "kon-kah-SAY") is a dice of tomatoes which have been peeled and the seeds removed.  Recipes that use concassé are striving for a finer result, showing that you cared enough about the quality of the final product to remove seeds, which can be tough and bitter; and the skin, which won't soften during cooking.

To make tomato concassé, start with fresh, ripe tomatoes.  Bring a pot of water, deep enough to cover the tomatoes, to a boil.  For each tomato, remove the tough part where the stem used to be by using the tip of a paring knife to carve a small cone-shaped piece out of the stem end.  Next turn the tomato over, and on the other end mark a small cross in the skin with the knife.  Each cut should be about an inch (2.5 cm) long.

When the tomatoes are ready, place a few at a time in the boiling water.  When the water returns to a boil, allow them to cook about a minute longer and then remove them using a slotted spoon.  Parboil all of the tomatoes in this fashion.  When the tomatoes have cooled enough to handle, slide the edge of a paring knife just under the corner of one of the intersections of the cross cut earlier.  Trap the skin against the blade of the knife by gently pressing with the thumb of the hand holding the knife and pull the skin away.  Continue to work around the tomato, removing all of the skin.

Two things will take some practice.  One is recognizing when the tomatoes have boiled long enough.  You don't want them to soften and get mushy, but you do want the skins to loosen.  The amount of time will vary, depending on how ripe the tomatoes are.  The other is learning how to peel the tomato.  It just takes practice and a bit of care.

Once all of the tomatoes are peeled, cut each in half around its middle, and gently squeeze out the seeds.  Sometimes you may find that you need to use your fingers ("impeccably clean" as Julia Child would always say), or a small spoon, to convince the seeds to let go.  Discard the skins and seeds.

After all of the tomatoes are seeded, chop them up.  Depending on the recipe and your inclination, this may be a rough chop or a fine dice.

Some cooks ignore the peeling and seeding and simply chop up their tomatoes for the recipe.  However, considering how little work it takes to make a concassé, it is sometimes worth the effort to produce a really top quality dish.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Chili Pepper Heat

I've heard that most of the heat in hot peppers is in the seeds and that if you remove them, the pepper will be mild.  Is that true?

--Robert

The active ingredient in peppers that makes them hot is a "capsaicin" (pronounced "cap-SAY-i-sin"), a  colorless, pungent, crystalline compound, C₁₈H₂₇NO₃.  The amount of capsaicin varies not only with the type of pepper, but with growing conditions and the degree of ripening.  The same pepper grown in hotter and drier conditions will contain more capsaicin and be hotter to eat. Heat from peppers is measured in Scoville units, starting at zero for sweet bell peppers and going to over 300,000 for Habañero peppers.

Capsaicin is concentrated not in the seeds, as is commonly believed, but in the fibrous, whitish pulp that holds the seeds, called the placenta.  As the pepper ages, capsaicin migrates from the placenta into other parts.  If you remove just the seeds and leave most of the placenta behind, you will actually do little to tame a hot pepper.  To get out most of the heat, you need to remove as much as of the placenta as possible, leaving only the fleshy outer fruit.

You can test this, preferably using a mildly hot pepper like a jalapeño, by dividing it into flesh, seed and placenta.  Going in that order, taste equal amounts of each part.  The amount of heat you experience should increase from fruit to seed and from seed to placenta.

Capsaicin does not dissolve in water, but does dissolve in alcohol and vegetable oils.  Drinking water has little long term ability to tame the heat of eating peppers.  Drinking whole milk or eating other fatty foods is likely to be more effective.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Vegetable Shopping

One way to save on grocery bills while serving top quality food is to be a conscious shopper, making sure that you are buying the best ingredients.  Not only will they taste better, they will handle more consistently and last longer in storage.  Here are some examples.

In the grocery store recently, I was picking over the green beans.  Another customer came over and also started to sort through the beans looking for good ones.  The bin had a mixture of nice, firm bright green beans, mixed in with some that were limp, likely from moisture loss.  Others were dark green with age.  You can also tell those because the seed inside is easily seen in the shape of the bean.  Some had brown or black spots, while others were broken.  Not that they were all bad.  Maybe about a third of the beans were discards.  While we shopped, a lady came over, grabbed a bag and stuffed in handful after handful of beans, without even looking at them.  She paid 33% more for the usable portion than the other shopper or myself.

I usually buy cauliflower from the open bin instead of getting a cello wrapped head.  While the stuff in the open bin may be a bit older, it is usually trimmed of any darkening on the head and has most of the scrap leaves and stalks trimmed from the base.  Last time, however, there was none in the open bin so I had to take a wrapped head.  When I got home, I trimmed and weighed the package.  The edible portion was 440 grams, just short of a pound, while the scrap was more than half of the total, making up 460 grams.  At $3.49 a head, that comes out to $3.60 a pound, or $7.92 per kilo, for the edible portion.   If I recall, the cauliflower in the open bin is about $6.00 per kilo.  At least, now I have a basis for comparison for the next time I go grocery shopping.

One of the new things in supermarket groceries, at least in my area, is tomatoes on the vine.  The idea is somehow that because they are on the vine, they are better.  I wouldn't disagree, but I never buy them as-is.  While making sure that the tomatoes I take have the produce sticker on them so that checkout knows what I am buying, I twist each tomato off of the vine.  Why? For two reasons.  First, I don't like to pay for the inedible stalk.  At least as importantly, if I take them as a bunch on the vine, I am frequently forced to take some that are over-ripe.  Under-ripe ones aren't as much of a problem, unless I plan to use them all immediately.  By picking the tomatoes individually, I save about 20% of the cost.

So, by checking carefully, I can save maybe 20 - 30% on the cost of produce, which translates to something like $8 - $12 per trip.

Oh, and to the nice lady who just stuffs handfuls of beans into a plastic bag, thank you.  By not picking through the produce you buy, you reduce the grocery store's wastage, which translates into lower prices for me.

---

If you have food or cooking questions, send them to Questions@KitchenSavvy.com
Due to the volume of questions received, not all can be answered.
© Lost Hobbit Enterprises 2004 onward

Black Spots on Potatoes after Boiling

Sometimes, when I boil potatoes, after I drain them I find gray or black spots on the surface.  What is this, and are they still safe to eat?

-- Marianna

Those spots are caused by a chemical reaction involving iron, the phenolic compound chlorogenic acid and oxygen.  Because it occurs more often at the end of the potato closest to the end where the stem was attached, it is called stem end blackening.  While somewhat unsightly, the color isn't as noticeable if the potatoes are mashed, and is not harmful, at least in the small quantities present.

The chemical reaction is more likely to happen in water that is more alkaline, so  blackening may be reduced by adding an acidic ingredient such as lemon juice, vinegar or cream of tartar to the cooking liquid.  In his book On Food and Cooking: The Science and Lore of the Kitchen, Harold McGee suggests adding the acidic ingredient after the potatoes are half-cooked.  The amount that you will need to add depends on the hardness of your water and the amount of water used to boil the potatoes.

Although some cooks like the added taste from using vinegar, I would suggest using cream of tartar, as it is the most neutral in terms of flavor, and trying perhaps 1/4 teaspoon in a pot of potatoes, to start.  If the blackening continues, try adding another 1/4 teaspoon.  If you can taste an unpleasant acidity in the final product, reduce the amount of acid added.

Preserved Lemons

What do you know about preserving lemons? Your favorite way to 
preserve them? Interesting ways to use them?

-- Dani

I, myself, have never made preserved lemons, but here is what I have been able to find out.  According to The New Food Lover's Companion, the lemons are "preserved in a salt-lemon juice mixture (sometimes with spices such as cinnamon, cloves and coriander) for about 30 days. Preserved lemons have a silken texture and a distinctive flavor. They're an indispensable ingredient and flavoring in Moroccan cooking".  Bacteria and yeasts acting on the lemons soften the rinds and deepen the flavor.

In Jewish cooking, there are two broad traditions, Ashkenazi and Sephardic.  Because Sephardic Jews are descended from those of Spain and Portugal, and because of the influence of Northern African cooking on the foods of those countries, preserved lemons show up in Sephardic cooking, too.

One Potato, Two Potato

Which Potato to use for which purpose?

On Friday my wife and I went to a new bistro in town to check it out.  Generally, the meal was good, but there was one notable disappointment.  For the starch with my main course, I ordered Potatoes Dauphinoise, a dish similar to scalloped potatoes topped with melted cheese.  In this case, the potatoes were cut into fairly large chunks, maybe about an inch (2.5 cm) to a side.  The insides were dry and grainy.  The mouthfeel was very unpleasant.  The reason was likely because the potatoes used were a high-starch variety, maybe Russets.

Potatoes come in essentially four kinds -- high-starch varieties like Russets, waxy ones like reds,  in-betweeners like Yukon Golds, and new potatoes, which are small young potatoes of any variety with thin, underdeveloped skins.