Broken lemon tart

[Lia Tumkus]

Hi everybody!

I was wondering if someone could explain to me why sometimes my lemon tart have cracks on the very next day I baked it. I've learn on my apprenticeship that one of the reason is the over baking, so I am always careful to get the tart out when the filling is still a bit jiggly.

I know in Heston Blumental's perfect lemon tart recipe the filling should reach only 72C but since I am selling this tarts I cannot keep poking it with a thermometer.

I'll be grateful for any inputs!

Cheers!

[Kerry Beal]

I wonder if an infrared thermometer would work well on curd?

[Lisa Shock]

If you bake with a water bath, you can temp that -just assume that it's about 5 degrees F hotter.

So, they are cracking the day after baking? How are you storing them?

[Keith_W]

I was once told that the tarts crack because they lose moisture. They then sink and crack. Check that you have blind baked your pastry enough - this helps stop it absorbing moisture from the filling. Also, try brushing the pastry with butter before you put the filling in.

[Lia Tumkus]

Kerry, I think infrared thermometer only reads the temperature on the surface, I'm not sure it's enough to tell the temperature inside.

Lisa, I do not bake it in water bath (maybe I should give it a try!) and I'm storing it in the refrigerator, cover with plastic wrap.

Keith, I am definitely blid baking my tart enough, usually I bake it until I get a nice golden colour on the bottom of the shell. I've never heard of brushing with butter, why does butter help?

Edited May 7, 2013 by Lia Tumkus (log)

[Keith_W]

Lia, the butter helps seal the pores of the pastry - in effect making it more waterproof.

[Lia Tumkus]

Cool! Thanks Keith! I heard about brushing egg whites but never butter, good to know!

[DianaB]

Hi Lia,

When making lemon tart I bake the pastry case blind, lined with parchment filled with baking beans to keep the bottom flat. five minutes before the end of the baking blind time i remove the case from the oven, lift out the parchment and beans and then brush the inside with beaten egg yolk. The pastry case then goes back into the oven for the final five minutes.

I've never had a problem with cracks to the finished tart so perhaps the egg yolk works as Keith suggested in respect of the butter, sealing the pastry to prevent it absorbing the lemon cream. The recipe I use, including this method for the pastry, comes from Michel and Albert Roux's Patisserie book. Everything I've attempted from that book has worked, it is still available through Amazon.

Hope that helps,

Diana

[Lia Tumkus]

Thanks for the input DianaB, sealing the pastry case is something that I definitely haven't done.

I was reading my post now and I just realize maybe some people didn't get that my problem is with the filling, my lemon filling is breaking down not the actual pastry. Did you understand that as well? Now I feel a little bit ashamed, sorry if my english/writing wasn't clear enough

[Keith_W]

Lia, I understand that it is your lemon filling which is breaking down. However, it is probably breaking down because the filling is losing moisture - and this is because the moisture is being absorbed by the pastry. And don't worry, there is nothing wrong with your English

Here is another trick for you - try using duck eggs instead of chicken eggs. The guy who told me about the lemon tarts is a former professional pastry chef who specialized in egg tarts He said that duck eggs are much less likely to split, but he never did explain why or how. In any case, they taste better!

Edited May 10, 2013 by Keith_W (log)

[Lia Tumkus]

Thanks for all the tips Keith_W I'm doing another tart on monday to test all the tricks I can. I'll see where I can find duck eggs...

And thanks for all your support

[JeanneCake]

What size tart are you making? Does it crack only in the center? Or is it shrinking from the edge? Or both? When you make the lemon curd, do you pour it directly into the tart shell and then cool and refrigerate or do you bake it for a few minutes? Do all of the tarts crack or just some of them?

[cecile12]

Hi Lia,

Do you let your tarts set at room temperature before putting them in the fridge?

Cooling them too rapidly or unevenly can make the filling crack.

Do you put flour or corn starch in your filling? Try without if you do.

Hope this can help you,

Cécile

[leopardots]

I use liquid pastry to seal the tart in then bake at about 90ºc. I find the longer slower cooking process helps, also, room temperature cooling is essential.