hazelnut crumble bundt cake

Why & how sour cream is used in cakes

You can make a cake with very few ingredients, equal amounts of flour, butter, eggs and sugar will give you a delicious pound cake. However, you can tweak the flavour and texture of your cake in an unlimited number of ways. For instance, we’ve discussed why you would use zucchini or carrots (even purple ones!) in a cake and how you can replace the eggs with corn starch. Of course there’s plenty more interesting variations to make.

Using sour cream is just one of those variations, which we tested out when making a recipe from Sweet, one of Ottolenghi’s cookbooks. Specifically, it asked to mix the baking soda with the sour cream (and yogurt) on forehand. As always with recipes from Sweet, it turned out great. But it did get us wondering, why even use the sour cream in your cake? What does it do, and how best to use it?

What is sour cream?

Sour cream truly is what the name says it is: a sour cream. In other words: cream that has turned sour (on purpose). In most cases micro organisms as used to make the cream turn sour. In doing so, it also thickens the cream somewhat and creates a lot of other flavours within the cream.

Since people did not have access to refrigeration like we do nowadays, the milk would be stored at room temperature. Milk is full of nutrients for micro organisms and as such microorganisms such as bacteria, yeasts and moulds could grow in the milk. These micro organisms produce all sorts of flavours and can make the liquid sour. Sour cream, but also creme fraiche for instance, originate from this natural process. Nowadays the process is a lot more tightly controlled, but still based on those same principles.

Sour cream characteristics

The growth of bacteria is what gives sour cream its specific properties. The bacteria produce all sorts of flavour molecules, such as diacetyl and also thicken the cream. This thickening occurs mostly because of the acidity which affects the behaviour proteins (caseins) in the cream. It is somewhat similar to what happens when making paneer cheese.

slice of hazelnut crumble bundt cake with sour cream
A delicious soft, fluffy cake, using sour cream as part of the batter.

Why to use sour cream in your cakes

There are actually a lot of reasons why sour cream may be used in cakes! We’ll tick of the most important reasons. Understanding all these nuances and differences between ingredients is what will make you a better cook/chef in the long term and help you to develop new delicious recipes!

Thickness

The first, most commonly mentioned reasons for using sour cream is its thickness.

If you’re baking a cake you are looking for a certain consistency of your batter. You want a batter that is not too runny or it will not be strong enough to hold onto any air that is formed and expanded during baking. At the same time, you want it to be runny enough to properly expand during baking.

Since sour cream itself has a consistency which is not too far off from that of a cake batter, it can be added quite easily without really affecting the consistency of the batter that much. This can be very beneficial if you’d like to add some more moisture to your batter, but already have quite a liquid batter. Adding something such as orange juice would thin your batter too much, whereas sour cream won’t have that much impact.

Browning of your cake & sour cream

When making a cake your recipe has to be sufficiently balanced so that it bakes on the inside, without burning on the outside. Of course temperature plays a big role here, but so does the composition of your cake batter. The main players in browning of your cake are proteins and sugars. More proteins and sugars will speed up the reaction.

Let’s compare butter and sour cream here. Butter contains very little lactose (a sugar) whereas sour cream tends to contain 3-4w% of lactose. This will make a recipe with sour cream instead of butter brown a little faster in the oven! That said, the low acidity of sour cream will slow down the browning reaction again! What the final effect will be will depend on whether there are other sour ingredients as well (in which case the extra acidity of sour cream might be less important) or how much sugar is there in total.

Activating your baking soda

Most cake recipes use some sort of a leavening agent such as baking soda or baking powder. These help to create a light and airy cake by releasing gases during baking. These gases help your cake to expand.

Baking soda and baking powder are very similar (which we discuss in more detail here). In fact, one of the ingredients of baking powder is baking soda, so both have baking soda as their active ingredient. Baking soda only works as a leavening agent if enough acid is present. In baking powder this acid has already been added, but baking soda requires you to add something acidic. Sour cream can be this sour component!

Generally, you wouldn’t use sour cream, just to activate the baking soda though. In that case you could also just use baking powder. However, you do tend to use at least some baking soda if you have sour cream since it neutralizes some of the acidity. A sour cream cake definitely does not have to taste sour.

Richness

Sour cream is made from cream and such contains a decent amount of fat. You add fat to your cake to make your cake richer. Cakes without any fat tend to be light and delicate, but drier (e.g. Angel food cake). Cakes with fat are less delicate but are richer and creamier (e.g. pound cake).

hazelnut crumble bundt cake

Alternatives for sour cream

To summarize, sour cream can be used in cakes to: add moisture without thinning the cake batter, adding fat for creaminess, controlling browning and to activate baking soda. The sour cream does all of this thanks to its high fat content & acidity. If you want to replace sour cream, you’d want to know why you’re using sour cream (is it because of the acidity or creaminess for instance). Then you’re able to decide which one to use.

Buttermilk and lemon juice for instance would be a good replacements to get that acidity, but they lack the fat. The most universal replacement would be a (thick) yogurt.

Sour cream vs (Greek) yogurt

If you’re using sour cream to add some extra moisture, while keep the consistency the same a good alternative would be yogurt. It’s also somewhat thicker, but contains a lot of moisture as well. However, there’s an interesting difference here. Apparently, sour cream contains less casein proteins than yogurt. Casein can improve the fluffiness of a cake, so using sour cream will make a less fluffy cake than using Greek yogurt.

Using sour cream

Overall, you will find that sour cream is often used to improve the texture of a cake and maybe to cut through some of the sweetness, thanks to its acidity. A lot of recipes will ask you to pre-blend the sour cream and baking soda at the start. The reason for this remains vague. If you want the sour cream and baking soda to neutralize in pH at the start, this will definitely do so. However, in the process of doing so, the baking soda will loose most of its leavening power (which is why you will often see baking soda being used in these recipes as well). In some cases this might actually be desirable though.

Yield: 15 portions

Sour cream cake

Sour cream cake

Even though the cake is made with sour cream, it definitely doesn't taste acidic. It does have a very pleasant crumb.

This recipe is based on a similar recipe from the book Sweet.

Prep Time: 20 minutes
Cook Time: 50 minutes
Total Time: 1 hour 10 minutes

Ingredients

  • 380g sour cream*
  • 1,5 tsp baking soda
  • 3 eggs
  • 280g sugar
  • 250g butter
  • 1 tbsp brandy
  • 2 tsp vanilla extract
  • 460g flour
  • 2 tsp baking powder
  • 1/4 tsp salt

Instructions

  1. Mix the sour cream, yogurt and baking soda and leave on the side for approx. 15 minutes.
  2. Mix the eggs, sugar and butter. Ideally the butter is room temperature so it mixes in easily.
  3. Add the brandy and vanilla extract to the egg mixture.
  4. Carefully mix the sour cream mixture with the egg mixture. You can use a stand mixer at a low speed.
  5. Gently fold in the flour, baking powder and salt into the mixture. Do not mix for too long or you will start developing gluten which will make it less airy.
  6. Pour the batter in a Bundt cake pan.
  7. Bake in a pre-heated oven at 180C for 40-50 min.

Notes

*Instead of sour cream, you can also use full fat yogurt. The texture will be slightly different, but its crucial effect on the baking soda is similar. You can also use mixtures of the two.

Sources

Harold McGee, On Food and Cooking

Khymos blog, Maximizing food flavour by optimizing the Maillard reaction, link

Serious Eats, How to make sour cream pound cake moist and tender every time, 9 June 2017, link

USDA national nutrient database, link

P. Walstra et. al., Dairy science and technology 2nd edition, 2005, link, p. 368 (Table 13.4) & 552

7 comments

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  • You explain things very well! Thank you so much! You’ve made it seem like I could us sour cream in a cake recipe without feeling nervous about it! Thanks for that also!!

  • Do you think using sour cream in a box cake mix is a good idea? Shou”d I use the sour cream in place of anything in the box cake mix? Like water or eggs?

    Thanks for your help,

    • Hi Katie, good question! It will depend a lot on your cake box mix on how it turns out. You could for sure always try of course :-). A lot of box mixes though have been optimized to create smooth soft cakes through the addition of other ingredients so you shouldn’t need it. If you’d like to try, I would decrease the water content since sour cream contains a lot of water. If your box states to add both water and oil you might want to decrease both.
      Sour cream contains about 20% fat. So if you decide to add 100g sour cream, reduce the water content by 80g and oil by 20g.
      Good luck!

  • You never covered why the sour cream and yogurt are mixed with the baking soda and rested beforehand. Is the baking soda’s only purpose to neutralize the PH of the sour cream? Would this not still be accomplished using the standard method? Could you not use the base acidity of the sour cream to also use the baking soda as a leavener by mixing some, if not all, of it at the end, reducing or removing the amount of baking powder needed?

    What is the benefit of not treating this like any other quick bread and minimizing the time between the wet ingredients and baking powder/soda touching, and getting the baked good in the oven?

    • Hi Matt,

      Great question! I did indeed not answer the question so just updated the post. The reasons for doing this are pretty vague as far as I could find and reason through. Here’s my thinking:
      If you use sour cream for its texture, but don’t want to have an acidic taste, you’d want to neutralize the acidity. The baking soda could do this. However, if you don’t need this baking soda for leavening (because you’re using baking soda for instance) you want to make sure that it has finished its work before adding it to the batter. In this case you really use the baking soda for flavour development and not any leavening. Most recipes I came across that use this method do indeed use baking powder as well, so that would explain it.

      What do you think?

    • Hi Denise,

      Good point! This recipe originally contained hazelnuts, but in the latest update we made the recipe more generic and forgot to remove the hazelnuts! If you want though, it’s easily implemented. Take about 100g of finely chopped hazelnut and fold them through the batter just before baking.

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