Ah, curdling. The bane of my ice cream making existence. I can't count how many custards have been sadly ruined after several minutes of infusing, carefully tasting and adjusting, tempering, slowly heating/stirring, and then... #^$*! One second too many turns perfectly smooth, thickened custard into egg drop soup. This is probably a testament to my somewhat reckless attitude towards cooking, as I'm sure this rarely happens to other ice cream making people. Or at least, multiple times.
Sure, people say you can "save" a custard by blending it back into shape, which I did once to some ginger ice cream (it was a holiday emergency), but it doesn't come out as good as it could be. So what's the idea behind curdling anyway? And how can we prevent curdling of any custard?
The Inquisitive Cook (Accidental Scientist) states that "In both cooked and stirred custards, setting happens at temperatures well below boiling. Cooking at too high a temperature or for too long toughens proteins and squeezes out liquid. This makes a baked custard "weep," and a stirred custard curdle--both signs of overcooking."
So temperature matters, as one would expect. But they also claim that it is the rate of heating that matters: "When egg proteins are heated quickly, there's a very small temperature difference (just a few degrees) between thickening and overcooking, so that custards seem to curdle instantly. When heated slowly, this range widens to 10° F or more." This is why some recipes call for use of double boilers for stirred custards, since they allow for a longer "grace period" before reaching the curdling point. Stirring is important for even heating throughout the custard, and not allowing one region (say the bottom) become overheated.
Ok, so now I have my double boiler and low heat. Wouldn't it be great if, with the help of my trusty thermometer, I knew exactly what temperature to look out for to prevent overcooking? This website says I can, with a greatly oversimplified formula. Unfortunately, application of this rule does not work. As described in Experimental Cookery, From the Chemical and Physical Standpoint, "The temperature at which coagulation (thickening) starts varies with the varying proportion of ingredients of the custard and the rate of cooking." So what works for my recipes won't work for someone else's, in other words.
On a related note, a few weeks ago I was reading an ice cream recipe on a popular blog that said to heat the custard to exactly 84° C (183° F). Of course, this was before I read about curdling, and so I thought "Oh great, a guideline for what temperature to heat my custard up to!" Next thing I knew, I had a curdled mess on my hands. What does help is keeping a thermometer in and taking note of approximately when thickening occurs. This way, from that point on you'll have a rough guideline (assuming the same proportions are used) of when to stop.
And lastly, with this newfound knowledge I made a delicious and beautifully pink strawberry basil ice cream! Simply use this recipe by Emeril (I cut it in half), but infuse the milk and cream with bunches of chopped fresh basil leaves for one hour. I also added a pinch of salt and half a packet of gelatin as described here. For presentation, I sprinkled the top with crushed dehydrated strawberries picked out a box of cereal, hehe. Wrong season for this flavor I know, and in summer it would be twice as good and refreshing, but keep it in mind until then!
Posted at 7:54 PM
Made with the Thomas Keller chocolate chip cookies, plus strawberry basil ice cream (post coming soon!). Sorry Ode, this flavor turned out awesome I must say, but next time I promise not to be too tired for ice cream making! The chipwiches looked and tasted good, but the cookies (and chips) were too rock-hard. That got me thinking, what's the best way to make cookies suitable for chipwich-making rather than for eating? Because for eating on their own, I like my cookies a bit crisp on the outside, chewy on the inside rather than chewy all around. How to best make them chewy all around?
The first thing I noticed was that size matters--I made two sizes of cookies, one about 2.5 inches in diameter, the other 4 inches in diameter. The 4 inch cookie remained soft the next day, at least in the middle, whereas the smaller cookies became rock-hard. Unfortunately, I used the smaller cookies for the chipwich, which really didn't work very well. I smushed the whole thing just by taking my first bite.
Second, I cooked them all too long for them to be chewy. In order to be chewy, the cookies have to retain sufficient moisture contributed to the dough by the eggs, butter, and brown sugar. Baking the dough for too long in the oven allows for increased evaporation of this moisture, making for an overall drier result. I basically left them in until the edges browned due to caramelization of the sugars in the dough, causing dehydration. So next time, I would want to use a shorter cooking time to preserve that moisture.
And lastly, a thicker cookie would also help. Shorter cooking time would help this, but to affect the thickness in a very significant way, I think the recipe would have to change. Which would subsequently affect the flavor, perhaps in a negative way, something like adding flour to thicken the dough. Well, shorter cooking time and bigger cookie diameter is a start, I suppose. Oh, and smaller chocolate chips. Because the chips were self-cut from a bar, I ended up with quite large chunks--which really hurt your teeth when bitten into frozen. What are your tips for making a better cookie for chipwich-ing? Any favorite chipwich combinations?
I must admit I've been neglecting the blog a bit these days, mostly because of various visitors that have come to stay with me, a gigantic "snowmageddon" that hit, and well, a hint of laziness. The recent snow storm has actually helped me get me off the couch/bed/lab bench and back into the kitchen (due to my school being snowed in for two days, yeah! So there are benefits to having the city wait for snow to melt rather than cleaning it up...). I recently bought Thomas Keller's new book designed for more casual, family-style home cooking, Ad Hoc at Home, and tried my first recipe. Of course it turned out to be a dessert, and something simple: chocolate chip cookies. I was just curious... What do Thomas Keller's chocolate chip cookies taste like?
The recipe was easy enough, although it really took the wind out of me to stir cookie dough without a stand mixer/paddle attachment. For chocolate, he uses a combination of Valrhona 70% and 55% chocolates. I cheated, and added half milk chocolate instead of the 55%. I know, all true chocoholics would turn their nose up at me right now, saying "Milk? Please, who eats that stuff anymore after age 10?" But I really do prefer milk chocolate over dark, even in my cookies. Not sure what that says about me, especially since I do enjoy lots of bitter things, like super-hoppy beer. What's your preference?
I made a few test cookies first, to see if I liked the dough I had or wanted to add anything more to it. First off, I forgot the salt! Terrible mistake, salt is such a big thing in desserts to bring out the flavors properly. Second--and this is probably after years of making the Toll House recipe on the back of the chocolate chip bag--I was missing the vanilla extract. I know, I doubt Thomas Keller uses vanilla extract, or extracts of any kind for that matter, in his cooking. But I ended up adding a teaspoon in anyway--my personal preference.
Overall the cookies were crisp on the edges, chewy in the middle, and tasted delicious. Not overly sweet, like so many of those pre-made dough kinds, and I think this recipe really makes the chocolate you use the star of the show. A lesson to use better chocolate--and more of it--next time. Anyone have their own chocolate chip cookie recipes or tips to share?