Bacalao Espuma

Scandinavia produces a lot of salt cod -- Tørfisk, Klippfisk, Clipfish. They can dry it in the cold air without worrying about spoilage. I first had it in Spain, as Bacalao, and fell in love with the slightly funky flavor it contributes to dishes.

For a Scandinavian dinner, I wanted a stable warm foam, or "espuma", to top a birch-wrapped, sous vide cooked cod fillet. I wanted to double-down on the cod.

From previous attempts, I've found it hard to keep a foam stable at high temperatures: whipped cream preparations are typically served cold. My additions of Agar Agar and even Xanthan Gum (in small amounts) didn't help much. I was looking for something almost as thick and solid as whipped cream, or at least shaving foam.  Ferran Adriá refers to these warm temperature foams as Espumas so I will follow suit.

Here, I synthesize what I hope is a simple but stable Bacalao-flavored espuma. This is a condiment so I don't need a ton; I'm targetting a 1.0L iSi Thermo Whip so a maximum of about 0.5L product.

To top 6 filets

• 250     g       Bacalo, bone- and skinless, rehydrated and desalted
• 250     g       Potato, peeled
• 250     ml      Heavy Cream

Rehydrate the Bacalao and soak in water for 2-3 days, changing the water 2-3 times a day to remove much of the preservative salt.  Cut it up fine so it will stay submerged in the Cream.

Simmer the Bacalao very low in Heavy Cream to infuse flavor, 30-60 minutes. You don't want it to bubble and reduce. (A sous vide bath might be helpful for this).  [I might need more Cream to Bacalao]

Meanwhile peel potato and cube, and boil 20 minutes until just cooked.  (Can I just cook the potato in the cream for 20 minutes?)

Thoroughly blend cooked potatoes and Bacalao cream, preferably in a Vitamix. While it whipped, it did NOT create a whipped cream: this was in retrospect a bit of a surprise; why not? Does this bode ill for the espuma?

Strain through coarse then very fine mesh seive. This gave me 400ml of bacalao-potato-cream.

Pour into iSi Thermomix. Check your volume, it should not be more than half full.  Charge with 2 N2O cream cylinders and shake vigorously. Hold in a water bath at a max of 75C (165F) until ready for service.

Resources

Below, I cite a number of recipes and resources from around the web. Some use additional flavors (shallots, coconut cream, chicken stock, cheese) but I wanted to let the Bacalao flavor dominate. The techniques I kept finding seemed to use heavy cream and potato: the fat from the cream will foam, and the starch in the potato may provide some stabilization.

iSi Potato Celeriac Foam (75C)

http://www.isi.com/en/culinary/for-professionals/recipes/recipes/recipe-of-the-month/?tx_isirecipes_recipes%5Brecipe%5D=1372&tx_isirecipes_recipes%5Baction%5D=show&tx_isirecipes_recipes%5Bcontroller%5D=Recipe

150 g Potatoes (floury)
75 ml heavy cream
75 ml Water
50 g Butter
75 g pureed celeriac
1 g Salt
1 g Pepper
1 g Nutmeg

Bring the cream and water to a boil in a pot and then, along with the boiled potatoes, blend into a fine puree. Add the pureed celeriac and the butter little by little then season to taste with salt, pepper and nutmeg. Pass through the iSi funnel & sieve directly into the 0.5 L iSi Whipper, screw on 1 iSi cream charger and shake vigorously. Keep the iSi Whipper warm at max. 75 °C in a bain-marie or in a water bath.

Espuma caliente de grasa de foie gras

http://vimeo.com/37517154
Xanthan 2.5g
Chick stock 300g
Whiz wiht immersion blenter very well
Add pepper, salt
Melt foie gras, add to Xanthan stock, whiz well
Striain, add to siphon
2 charges N2O
Hold at 70C

Potato Espuma

http://www.thestaffcanteen.com/recipe/potato-espuma/
600g cooked potatoes
450g hot double cream
150g hot milk
seasoning

Boil potatoes just until cooked, drain and slightly cool, peel and mash potatoes Add seasoning, add hot liquids and check seasoning adjust were needed, pass through double sieve, place into charger and use two charges and keep warm at 55oc

Pea Espuma (warm)

http://www.isi.com/en/culinary/for-professionals/recipes/recipes/vegetable-espumas/?tx_isirecipes_recipes%5Brecipe%5D=1104&tx_isirecipes_recipes%5Baction%5D=show&tx_isirecipes_recipes%5Bcontroller%5D=Recipe&cHash=635b0b38457dffc706c8fab2c5c212fc

200 ml heavy cream
100 g Peas
150 g Potatoes

Peel the Potatoes, cook until soft and mash with a potato masher. Blanch the Peas and puree in a blender until smooth. Heat the Heavy Cream, mix with the potatoes and the pea puree and season with salt, nutmeg and 50 ml mint oil. Pass through the iSi funnel & sieve directly into the 0.5 L iSi Whipper, screw on 1 iSi cream charger and shake vigorously. Keep the iSi Whipper warm at max. 75 °C · 165 °F in a bain-marie or in a water bath.

Potato foam 

250 g potatoes, peeled and cut into chunks
125 g single cream
30 g virgin olive oil, plus extra for drizzling

Place the potatoes in a pan of cold water, bring to the boil, and cook for about 20 minutes until soft. Drain, reserving 100 g of the cooking water. Place the cooked potato and the water in a blender. Purée, adding the cream little by little. Follow the same procedure with the oil until you have a smooth emulsion. Season with salt. Strain, then fill the siphon using a funnel.  Charge with nitrous oxide, shake, and keep warm in a bain-marie at 70 ºC.  Ferran Adria via http://www.chubbyhubby.net

elBulli Hot potato foam

http://www.foodsfromspain.com/icex/cda/controller/pageSGT/0,9459,35868_6908153_6910167_4459102,00.html
250 gr potatoes for mashing
100 gr potato cooking water
125 gr cream, 35% fat content
35 gr extra virgin olive oil
500 ml ISI siphon
2 N2O chargers
salt

Peel and cut the potatoes and place in cold, salted water. Bring to the boil and cook for approximately 20 minutes. When cooked, drain and reserve the water. Place the cooked potato and 100 g / 3 1/2 oz cooking water in the Thermomix at 60ºC / 140ºF. Blend and gradually pour in the cream. Do the same with the oil until a very thin, smooth emulsion is formed. Season with salt. Strain and fill the siphon using a funnel. Charge the siphon and place in a bain-marie at approx. 70ºC / 158ºF.