All have their merits but I found yoghurt gave me consistent results and a flavour that everyone in the family liked (kefir grains will give you a much more nutrient dense sour cream, but it does have a particular flavour that the kids don't really like, although Bryan and I do).

During my efforts I discovered some hints on websites, and ones that I experienced, which you may find helpful:

1. Always makes sure your cream is full fat (35%) and that it is pure cream (no gelatine, etc.)

2. Remove the cream from the fridge two hours before adding the culture (in my case yoghurt) so that it is well and truly at room temperature (I didn't do this initially and found it made a big difference to the culturing time)

3. I use a large clean 1 litre glass jar to do my culturing

4. Once the yoghurt is added to the cream it should be left in a warm environment (22 to 26 degrees) to enable the culture to do its magic in a reasonable time (24 to 48 hours) ... in the warmer months this is not an issue, but to do this in winter I place the jar on a plate, I then turn the oven light on and place the plate (with the jar on) close to the light and shut the oven door ... you would be surprised at the extra warmth the light creates in the smaller space

5. Once the cream is soured it goes into the fridge to chill where it will thicken further ... I then decant the sour cream into two smaller 300ml glass jars so that only one is removed from the fridge at a time keeping the other one fresh and chilled

6. Your sour cream can be churned into butter giving you cultured butter and leaving you with cultured buttermilk

7. I am aware that I use more yoghurt than necessary to culture 600mls of cream (usually it would be approximately 3 tablespoons ... about 70g), but I want to make it easy for me to remember so I know I can remember 600mls cream to 100mls yoghurt without checking my notes

8. Some websites state the soured cream will last 2 to 3 weeks in the fridge, but we usually consume it well within two weeks

The first attempts I made I didn't leave the cream long enough to culture properly and it didn't thicken up to the extent that I thought it would after it had been chilled ... if this happens to you please don't get rid of the cream ... it is still really good to use, and in each case I used it to make either frittata, omelettes, scrambled eggs, savoury baked custard dish (see here) or something similar for the family.

What I found too was that once I stirred the cream after the first 24 hours I could see it thickening as I stirred but it still wasn't quite thick enough to chill, so I left it for another 4 hours and stirred again at which time it had thickened up considerably so it happened quite quickly. Once it was chilled it was thicker again.

So the trick here is for you to find the right amount of time to allow the cream to sufficiently culture in your own kitchen (all kitchens have different temperatures based on their position and aspect within the home). So use my notes as a guide, penciling in your own times on them so that you know what to do in the future.