Recently I purchased and ice cream maker and have been making lots of sorbets with our surplus frozen fruit. Often I will follow a recipe however sometimes not: sometimes the sorbets are icy after just a few hours (even recipes) and sometimes incredibly smooth and creamy (even without recipes). I always churn the sorbet until a soft-serve consistency and always use a sugar syrup. What can I do to ensure a smoother sorbet and furthermore longer lasting?
The general things that can cause icy sorbet:
- Too much water Compared to other ingredients. Since you probably aren't going to take water out of your fruit, you pretty much have to add sugar or alcohol to compensate for this. This is tricky if you're improvising, and if the water content of the fruit varies.
- Bad churning/freezing: This is mostly determined by the ice cream maker you have. It sounds like you're probably okay, since you get good results sometimes, but if the churning isn't good, you can get big ice crystals as it freezes around the outside before getting mixed well. If you're using the common type with a pre-frozen vessel, make sure you've frozen it thoroughly, so that you can churn long enough to smooth things out.
- Chunky fruit: Big chunks will be really obvious, but even tiny chunks can help provide little bits that make the result freeze hard. Make sure that you puree well.
- Too cold a freezer: sorbet is going to be best if it's not frozen extremely cold, but your freezer probably is nice and cold. Be willing to let it sit out a little bit before eating, or and perhaps keep it in the door where it's slightly warmer.
David Lebovitz has a good blog post about making homemade ice cream softer; most of what I've mentioned is also there, along with more details and some things that apply only to ice cream - for example, fat softens things too.
I bookmarked a blog post long ago that explains how you can make your own invert sugar to improve the texture of sorbet -- you use acid to break the sucrose down into a mix of fructose and glucose, which crystallize more slowly than the sucrose of table sugar does.
The machine will make a difference. I've found that home machines with a spinning bowl with a scraper that sits inside tend to make larger crystals and lose their freezing ability before the sorbet is quite set up enough. It makes good sorbet/icecream for same day use but if you hold it for too long (a day or two) it'll start getting grainy fast.
Commercial grade machines in restaurants will freeze and churn the sorbet more. The texture will be finer and it will keep for maybe a week before it starts to get grainy.
You also might be comparing sherbet to sorbet, which has the same ingredients but typically has the addition of either egg whites or dairy which gives it a much creamier texture without the fattiness of ice-cream.
Store bought sorbets will have additives that stabilize their product as well it gives them the ability to add more air so you get less raw ingredients but more smoothness.
Try using Pectin! It will enhance flavors and minimize the size of ice crystals. If you can't find it in raw form, use peach preserves (2tsp and you won't taste it). Check the ingredients to be sure it contains Pectin. It works well in Ice cream too if your not willing to use eggs (custard)
Food Science Teacher