Sweet Corn Ice Cream with Blackberry Swirl

1. Constantly stir: Do not walk away from the cooking custard. Continuously stir and scrape the bottom of the pot during cooking. It only takes a few moments for the custard to sit too long in one place and clump up. The fat, sugar, and water surrounding the egg proteins help lower the chance of scrambling, but it remains a concern. A few clumps might form here and there. You can strain them out but try to keep the custard as smooth as possible. I highly recommend using a spatula instead of a whisk, because a whisk doesn’t reach all the corners of a pan or fully scrape the bottom.

2. Watch your Temperature: Keep a temperature under 180°F (82°C) while thickening the sweet corn ice cream base. At this temperature, the eggs (protein) in the mixture scramble and clump, which causes the custard to break. I like to maintain between 170-175°F (76-79°C), to be on the safe side. But the mixture will thicken at anything over 140°F (60°C). At this temperature, egg yolks cook. Cooking at this low a temperature works, but it also takes a very long time to reduce and thicken.

2. Use a double boiler: Add about 1in (2.5cm) depth of water to a saucepan and place a heat safe bowl over the top of the pan. Turn the burner to medium/med-low so the water begins to simmer (NOT a rolling boil) and heat the bowl. Add all the tempered custard to the bowl and stir until the mixture has thickened and passed the spoon test. This step takes longer with a double boiler, but you have far less of a chance to scramble it. With a double boiler, the custard isn’t directly touching the pot, which is touching the heat source, so there is less intense heat transfer.

So, I know the go-to descriptions are coating the back of a spoon/spatula and fluidity after running your finger over the coated utensils. But quite a bit of nuance exists even in those phrases.

Here’s a larger description from uncooked to over-cooked crème anglaise (ice cream base) to help you out.

Stage 1: During the first 5-7 minutes at medium-low/low heat, the ice cream base remains very liquid. If you dip a spoon into the mixture and look at the back of it, the liquid beads up and runs off the spoon.

Stage 2: Over the next 15-20 minutes, the custard thickens and starts looking like fruit nectar or buttermilk. There is also a slight resistance as you stir. But the mixture moves easily, with the liquid trailing slightly behind the spoon instead of splashing freely. Look for a gentle swirling motion, with visible ripples forming on the surface. The cream coats the back of a spoon at this point. However, if you run your finger along its surface, the cream still runs too much. The coating looks thin and very see-through.

Stage 3: You shouldn’t have more than 5-10 minutes left at this point. Use the spoon test every 2-3 minutes until the cream doesn’t run back and looks hazy on the spoon. You should be able to turn the spoon gently side to side and not have the cream shift into the separation you made. (YOU’RE DONE!)

Stage 4: If you continue to stir and let the custard thicken into the consistency of caramel syrup, honey, or condensed milk, you cooked your custard too long. This does not mean you overcooked or scrambled it. It simply means that you evaporated too much moisture out of the ice cream base. And the less water in the ice cream base, the softer it will stay and faster it will melt.

You can completely negate the need to chill before spinning the custard, as long as you get the ice cream base down to 43°F (6°C) before churning it. To do this, nest the cooked sweet corn ice cream bowl into a larger bowl filled with ice. Stir until the aforementioned temperature is reached. You may need to add more ice or completely change out the larger bowl with fresh ice. Then, finish the recipe as written.

Of Note: Omitting the long chill time has a trade-off. Without that time to infuse, mellow, and become uniform, the ice cream’s flavor stays less developed.  

So, I know you noticed me using the words crème anglaise in this recipe. What is it? Crème anglaise is a sweet cream custard sauce that makes up the base of French-style ice creams. It’s also a popular pour-over sauce for hot pastries and cakes, like apfelstrudel (apple strudel). You don’t need to churn it to ice cream when you can drink and dip right from the bowl, right?!

– American ice cream is made with milk, cream, sugar, and flavorings. It has a very high milkfat content to get around its lack of egg yolks as stabilizers, think 14-25% milkfat. American ice creams’ volume changes drastically during the churning process, sometimes exceeding a 50% increase in volume. That’s a LOT of air!

– Italian ice cream or gelato, like American ice cream, does not use eggs. It also uses more milk and less cream than all other ice creams. Gelato usually has a milkfat content of around 4-9%. Gelato gets its density and creaminess from how slowly it’s churned and from the warmer temperature it’s served at. Gelato is so beloved, because it doesn’t build up a coating of fat on the tongue, the way ice creams with higher heavy cream contents do. (see OF NOTE)

– French ice cream or crème glacée also uses egg yolks, but sometimes fewer yolks by weight than frozen custard. French ice cream’s custard base always cooks before churning. Any ice cream that uses less than 1.4% egg yolks and more than 10% milkfat must be labeled French ice cream in the U.S. The change in volume (overrun) typically won’t be more than 40% after churning.

– Frozen custard includes at least 1.4% egg yolks by weight and more than 10% milkfat. The volume should not increase by more than 30% when churning. Originally, frozen custard was made in small batches, to preserve freshness and wasn’t heated before churning. But commercially it has to be pasteurized to kill any bacteria before churning.

Of Note: No–churn ice creams notoriously create a layer of fat on the tongue, because they are made from sweetened, frozen whipping cream. I like no-churn ice cream recipes, because they are quick and approachable. I have two recipes for them myself. But, in my opinion, they are just not as enjoyable. Maybe that’s also a good thing. It’s like built-in portion control. 

If you decide not to use all of the syrup in the ice cream, try this cocktail recipe. Mezcal, Blackberry Shrub Cocktail. It’s fruity and tart and smokey, the perfect trifecta if you ask me. You will need between ¾ – 1oz (22.5 – 30ml) of blackberry syrup per cocktail for this. Simply mix a touch of vinegar into the syrup until it has as much pucker as you like. Then mix up the cocktail with the remaining ingredients at their listed amount. I know the sage is only a garnish, but it is necesary to the cocktail. Do not skip it.