What makes lemon bars tart?

February 25, 2011 1:01 PM

What makes lemon bars tart?

Question for bakers, pastry chefs, homecooks: I have made tons of lemon curd in my life satisfactorily from one recipe. Though lately I've made 3 batches of lemon bars, trying to get them just how I would like them. I've come to a consensus about the cookie base (though it's not what I originally intended). However I can't get the curd tart & bold enough. The first bars I made from Smitten Kitchen had great flavor but were totally sticky and unwieldy. The CI recipe was the opposite, very practical texture but muted flavor. I've been comparing: 2 Cook's Illustrated recipes, Smitten Kitchen's variation on Ina Garten's recipe, Alice Waters' curd recipe, Nigella's curd recipe using lemons, Amy's Bread's recipe, David Liebovitz's recipe, and Rose Levy Birnbaum's Ultimate Lemon Butter Bar recipe. I've come to believe that the final adding of milk or cream to the curd off the heat before going into the oven mutes the lemon flavor. Is this right? This is just a guess based on this very amateur chart, as well as the fact the the Smitten Kitchen curd and Nigella's curd without milk are easily bold & tart compared to the 2 batches of CI lemon bars that I've made that have milkfat in them. I wish I knew why CI decided to use cream instead of regular milk as others do. It made me think that it's the milkfat they're looking for.

What is muting the lemon flavor? The additional yolks? The milk protein? The milk fat?

Thank you!

posted by scazza to food & drink (26 answers total)

My favorite curd recipe uses egg yolks and butter, but no milk or cream. The butter helps with the creaminess, but it keeps the strong citrus flavor. I also put a ton of zest in there for brightness.
posted by freshwater at 1:04 PM on February 25, 2011

I wonder if it's the salt - one CI recipe calls for 1/8 tsp salt while the Nigella recipe doesn't (I'm not going to check all of them). Salt should act to make your bars taste sweeter and less tart.
posted by muddgirl at 1:06 PM on February 25, 2011

I meant "1/8 tsp salt in the filling".
posted by muddgirl at 1:06 PM on February 25, 2011

I've never made either of your recipes, but I would tend to agree with freshwater on this. Milk and cream do dampen tartness, so I think that's probably your culprit.

And you can't go wrong with more zest.
posted by phunniemee at 1:10 PM on February 25, 2011

freshwater - yes that's the Nigella recipe's same tack (the one I linked. She has another one that does use milk. Gah!). That's exactly what my question is about. But lemon bars are a bit more complicated because you want the texture to set, where in curd you don't.

muddgirl - salt should enhance, though sugar does the same thing, hence why some recipes leave it out.
posted by scazza at 1:10 PM on February 25, 2011

phunniemee - I agree about zest which is why I've been actually blending an entire lemon as in Liebovitz's recipe. We had sliced some lemons on top in my first batch, now can't live without that element. But still, it wasn't very bold! More zest and more lemon juice I'm not convinced are the answer.
posted by scazza at 1:12 PM on February 25, 2011

I forgot explicitly part of my question which is: why do most recipes add milk in the first place? It's not needed for regular curd texture at all to "bring the elements together."
posted by scazza at 1:16 PM on February 25, 2011

In all of my lemon recipes, I replace a portion of other liquids with lemon juice. I've done half and half for a really lemony flavor, or some times one part lemon to two parts whatever other things are. Mouth-puckeringly delightful.
posted by chatongriffes at 1:22 PM on February 25, 2011

I love your chart and your enthusiasm for figuring this out!

I wonder if substituting gelatin (perhaps made with lemon juice) would help increase the tartness while keeping the desired texture?

I didn't see any discussion attached to the Cook's Illustrated recipes and think it's an oversight not to explain the choice of heavy cream. But generally, my thought is that lemon bars have historically not been intended to hit you over the head with tartness, and the dairy is one way of guaranteeing that they're on the milder side. I've primarily seen lemon bars in the context of rather bland cookie/brownie selections at bakeries with traditional selections or at buffets intended to please everyone. CI doesn't generally cater to cooks who want bold and surprising results...
posted by paindemie at 1:58 PM on February 25, 2011

Alice Medrich has published a recipe in her new cookie book which she says is very tangy, so tangy that "an esteemed New England cooking magazine once pronounced [them] too sour." It's been copied word for word at this blog (with which I have no affiliation; I just have the book and the recipe is identical.)
posted by fingersandtoes at 2:21 PM on February 25, 2011 [1 favorite]

Someone on Chowhound suggested adding salt, adding more zest, and adding "sour salt" to both the crust and the filling!
posted by barnone at 2:38 PM on February 25, 2011

And here's some extra-tart lemon bars.
posted by barnone at 2:41 PM on February 25, 2011

fingersandtoes & barnone - See, the SK recipe uses flour as well and I found it problematic and sticky. I have liked the CI texture. The Alice Medrich recipe is basically the same proportions of yolk to sugar & lemon as the others.

Sour salt is an interesting idea. I have it. Heather S's recipe is interesting for the really high amount of sugar, about a 1/2 cup more than I'm used to seeing.
posted by scazza at 2:50 PM on February 25, 2011

It is VERY notable that neither of those recipes use any butter or milk and both are consiered very tart. No milk product at all and flour instead of using more yolks. So it must be something with the dairy. Definitely leaving the milk out is a must. SK didn't use any butter either (though Nigella's curd does and that doesn't interfere with bold flavor, so I didn't think it was the butter's fault).
posted by scazza at 2:55 PM on February 25, 2011

Is it not simply that milk is a base and lemon juice an acid, and you're altering the Ph of the curd?
posted by Diablevert at 2:59 PM on February 25, 2011

I've never made a lemon bar recipe with milk or cream. I'm sure some people do because they prefer things less tart.

A lot depends on the fruit itself- meyer lemons are less tart. Adding more zest will make them more lemon-y, but not more tart. You need more acidity for the tartness. You can add a little bit of citric acid to the curd if you want to boost it, or use some lemon juice concentrate, or try reducing the lemon juice by heating.
posted by oneirodynia at 3:05 PM on February 25, 2011

Add me as another data point for never having seen cream or milk (other than butter) in the lemon mixture.
posted by smirkette at 3:22 PM on February 25, 2011

What kind of lemon are you using? If you're using Meyers, that's your problem.
posted by Sys Rq at 4:11 PM on February 25, 2011

I have several times made a shaker lemon pie (a la Sue Hubbell) wherein I thinly slice two lemons and mix the slices with sugar and egg yolks, dump that into a pie crust, lay on a top crust, and bake. If eaten that day, it's insanely tart. If I let the mixture sit in the fridge overnight or wait a day to eat the pie, it's mild.

So, time is a factor.
posted by neuron at 4:15 PM on February 25, 2011

I noticed in David Lebovitz's post he mentioned a baker told him that lime juice was his secret.
posted by Lyn Never at 5:11 PM on February 25, 2011

Sys Rq - I've used both kinds of lemons and it's not the problem at all. Sorry to disappoint. Meyer lemons were used in the bars that were significantly tart enough, in curds that are tart enough, and I've also used them in my shaker lemon pie. They have better skins for those of us who like the skins and they're easier to juice. My most recent batch with regular lemons was not tart. The taste that I'm trying to eliminate is a fatty, buttery odd taste in a lemon bar that masks the lemon tartness. But I'm not sure if it's the milk, butter, yolk or something else.

Ideally I would like the consistency of a fatty bar, the ease of cutting, and the tartness of a flour bar. Maybe unattainable.

Where I am now is, compared to the CI recipe:
More tartness - no milkfat, maybe a pinch of lemon salt, more sugar since the tarter flour recipes uses more sugar
less forward egginess- less yolk so reduce from 9 yolks to 5 but add 3 tblsp flour to keep it together
Maintain ease of cutting - keep 4 tblsp butter
Love the peel - add Liebovitz whole lemon

3 large egg yolks, plus 2 large eggs
1 2/3c sugar or 1.5c sugar
zest from 1 lemon
Juice from 3.5 lemons
One whole lemon
Pinch of salt
4 tablespoons unsalted butter, cut into 4 pieces
3 Tbsp Unbleached All-Purpose Flour

The milk thing, yea, odd, but look at those recipes and the majority use milk. Even Alice Waters. However if you use flour rather than butter, more yolk, (and maybe also milk) it makes it kind of bubbly & separated. I did like the flavor of the SK flour bars, but the consistency was so sticky & separated.

neuron - I've found with all curds actually the opposite which is that the tart lemon bold flavor is not there right off the heat, but will develop as it cools in the fridge. Funny!

Lyn Never - my husband saw that too. But what I'm really interested in is all these recipes look legit, they're from legit people, yet all so different. One among them must be tart enough, must be what I'm looking for but why. I've narrowed it down to certain factors, but I'm just confused about the basics. Again, my first batch was tart enough, but I did not like the consistency.
posted by scazza at 5:18 PM on February 25, 2011

Ann Hodgman's "Beat That!" cookbook recommends citric acid aka "sour salt" which is derived from lemons and makes fillings more tart without thinning. She says it can be found in pharmacies, or sometimes in the pickling section at the grocery store. She uses 1/4 tsp. for a 9" key lime pie.
posted by sevenyearlurk at 5:46 PM on February 25, 2011 [1 favorite]

I find your dedication to the art of the lemon bar inspiring. As you and others have noted, I think milk,h/h,cream should be avoided...tho I love using homemade (ya know, or bought, whatevs) yogurt in place of milk. Density and creamy goodness with a lactic acid bite!

Also, do not underestimate the amazing power of a little tartaric acid addition. Natural, why your wine tastes so good, cheap and available online...what barkeeps use to foof up drinks.

Brilliant stuff.
posted by metasav at 12:03 AM on February 26, 2011

The milkfat in milk and cream does have a muting effect on the acidity of the lemons, and should be avoided if you want a really lemony bar.

I also wonder about your recipe--are you measuring the lemon juice using a liquid measure? "Juice from 3.5 lemons" could really vary depending on each lemon, and might contribute to the varying tartness of the bars. If you're not already, definitely use a liquid measure each time so you're comparing apples to apples, or lemons to...lemons.
posted by Bella Sebastian at 8:27 AM on February 26, 2011 [1 favorite]

I like my citrus very tart, and I notice that nearly all recipes call for too much sugar. I've cut the sugar in lemon curd recipes by as much as half without affecting the consistency of the curd. Maybe reduce it by a third to start and see if that gets you anywhere.
posted by fiercecupcake at 8:30 AM on February 26, 2011

FYI, inspired by this askme post, i made the lemon bars posted by fingersandtoes (on the seasaltwithfood blog), and they were AMAZING.
posted by Kololo at 6:49 PM on February 27, 2011