Last week, we had an overview on whipping siphons, discussed what they are and how they work. This week, we will go deeper and see how to get the best results out of the device that became the symbol of molecular gastronomy. Specifically, we will see how to obtain the desired outcome, avoiding disappointment and sudden change of dinner plans (see my Valentine's post, for ref :P).
1. Imagine the final outcome
A whipping siphon is meant to create foams, that's quite clear. What is not so obvious is the different types of foams we can get, depending on the content of fats, texture and stability. These three parameters are strictly related to each others. Think, for example, to two very common foams: whipped cream and cappuccino's foam. The first one is obtained by whipping fresh cream, while the second one by steaming some whole milk. Both of them are foams, but with very different textures :)
Think in advance about the type of foam you wish to create: a light one to pair a main course or a thicker one to garnish a dessert? For instance, a light citrus foam could be used as a base to serve an oven roasted fish. A chocolate foam can, instead, be ideal to give a final touch to a vanilla flan.
2. Calculate the percentage of fats
As explained in the chantilly's post, the percentage of fats affects significantly the stability of the final product. Light foams are poorer in fats than thicker ones, but also less stable. Think about the example of whipped cream and cappuccino's foam, in point 1. A whipped cream is relatively stable. Well, not stable forever, of course, but it allows you to prepare a dessert in the morning and find it intact the same evening, if stored in fridge. On the other hand, cappuccino's foam is not so long-lasting!
Do you understand now the mistake I did with my Valentine's dessert? The water contained in the strawberries diluted the fats, making a mixture that was impossible to whip. Despite all my efforts, I just obtained a light foam that was not appropriate at all to garnish my chocolate pudding.
Here, a few tips:
- Is your goal a thick foam, able to stand and keep a shape? In this case, the percentage of fat of your mixture must be about 33- 36%. In my case (strawberry foam), I should have used a decadent Devon cream with 48% fat content to be diluted to 33-34% with the addition of strawberries. Otherwise, I could have used dehydrated strawberries to blend with some fresh whipping cream (about 35% fat content).
- On the other hand, if you wish to obtain a lighter foam, you should decrease the percentage of fats. I recommend you stay around 15% for a decent result. Anyways, there are no fixed rules. Just remember that the gas used in the siphon, N2O, is fat-soluble. Therefore, be careful about minimizing the content of fats or you might fail your recipe. For example, you can't make a foam out of some lemon juice or of simply blended strawberries (not with a whipping siphon, at least), because the percentage of fats is minimal (to do not say zero...). Actually, it is possible to make foams starting from watery mixture, but they are created with a completely different method and are poorly stable.
3. Do not introduce any solid
This is crucial! Let's repeat it all together as a mantra: no solid particles, no solid particles, no solid particles in the siphon :)
Even the smallest seed can block the extrusion valve and compromise the functionality of your siphon. Unless you use straight whipping cream, here a few tips to do not get troubles:
- Always filter the liquid to extrude.
- If you use fruits and vegetables to flavor, peel them and remove the seeds before blending the mixture. This precaution will make the filtration step easier.
- Berries are particularly "insidious" as they contain very small seeds and are difficult to peel. With strawberries, you can remove the external part, which is the one containing the seeds. Things get more complicated with fruit as raspberries. In this case, I recommend to filter the mixture in two steps: first with a coarse mesh sieve and then with a fine mesh one. If you use a fine mesh sieve right away, filtration might take forever.
4. Use the right number of capsule
Siphons are usually available in two capacities: 0.5 and 1 L. With 0.5 L, we just need a cartridge of N2O, while for 1 L volume we need 2 of them. Always use the recommended volumes (0.5 or 1 L) of liquid and the right number of cartridges for best results.
5. Serve at the right time
Thanks to their stability (see point 2), thick foam as whipped cream can be prepared much in advanced and stored in fridge till time to serve. In light foams, instead, the liquid separates more easily from the gas phase. In that case, it is better to prepare the foam right before serving.
To avoid unpleasant surprise, I prepare all my foams express, namely just before serving. However, if you want to make them in advance, take into consideration what discussed above.
I hope this article was useful, if you have questions, please, let me know in the comments :) BTW, prepare your siphons, on Thursday, we'll start practicing!