Meringa con Zabaglione

Meringa con Zabaglione

This week, we made meringa con zabaglione e fragole (meringue tarts with berries and cream). The lab was broken into three parts. We made the meringues first because they require a long baking time.

After preheating the oven to 300 degrees, we separated the whites of five eggs into a stainless-steel bowl and beat them with a hand mixer until they were foamy. At that point, we added the cream of tartar and beat until the eggs formed soft peaks.

Soft peaks flop over when the beater is lifted

In a small pot over low heat we dissolved the sugar into the water. We heated until we reached about 240°F, which is the soft-ball stage. To test if we had reached the correct point, we drizzled some syrup into cool water. When it formed a soft ball, it was ready.

 Our sugar formed a soft ball when dropped in cool water

We then beat the eggs again, adding the hot sugar syrup slowly. We continued to beat the until the egg whites formed stiff, glossy peaks.

Stiff peaks stay standing on their own

We then lined two baking sheets with parchment paper and scooped spoonfuls of meringue into tart shapes using the back of a spoon. We also made a larger meringue as an experiment and a way to use up the extra we had made. We baked these for about 40 minutes at 300°F, then shut off the oven and left the meringue shells in for another hour.

When the meringues were about 40 minutes from being done, we moved on to the zabaglione. We put a small amount of water into a saucepan and brought it to a simmer, then placed a bowl over this pot and in it, whisked together the egg yolks, sugar, and wine. A double boiler could also have been used for this step.

Whisking the egg mixture over hot water.

As the mixture heated, we whisked constantly, and continued for about 30 minutes until the whisk left tracks in the zabaglione for a few seconds. At this point, we took the bowl off the heat and submerged the outside in cool water, still whisking as the zabaglione cooled.

The whisk leaving tracks in the zabaglione

Then, while the zabaglione was still hot, we poured it onto the finished meringues, and garnished with berries.

 Our finished meringa con zabaglione

Our experimental, large zabaglione, which browned beautifully but did not fully dry out in the middle.

• What chemical changes occurred when you made the meringue? What did you observe that told you these chemical changes were happening?

The proteins in the egg white denature, due to the agitation of beating and the acid added. The proteins then coagulate around pockets of air, creating a foam. This was apparent as the eggs turned white and eventually got stiffer, turning from liquid to foam. When the meringue was baked, more proteins denatured and coagulated due to heat, causing the foam to set into a solid.

• What was responsible for the thickening of the zabaglione as you stirred it over the hot water bath?

The zabaglione also thickens because of denaturation due to heat and coagulation, apparent when the custard “sets”.

• Overheating (too fast and or too hot) the zabaglione can leave you with “scrambled eggs” – a lumpy grainy mess of clumps in watery liquid. What is happening in this case?

Heating the custard too fast or too much causes the proteins that denature to curdle. Instead of coagulating with water, sugar and fat molecules trapped between the proteins, curdled proteins clumps together excluding these other molecules, leaving tight curdled lumps swimming in a water, sugar and fat mixture.