Vegan Yogurt

I've been making my own yogurt for a while, using some of each batch as the culture for the next. It's been a largely successful process (with one unfortunate incident using milk that was about to expire). Needing something yogurt-like for a vegan meal, I intended to make my own. Vegan yogurt sounds like it should be an easy extension of the process (just use soy milk instead of dairy, right?) but suffers from one simple problem: yogurt cultures are based on milk products. The cultures I use are just remains of dairy-based yogurts. The powdered cultures in supermarkets are pre-mixed with milk powder. The only dairy-free yogurt I could find in shops was sweetened and flavoured. Not only does this mean it has the wrong taste for cooking, but flavoured yogurt is also largely useless as a culture.

So I tried searching further afield, checking health food stores in and around Canberra. Several of them had yogurt cultures ready to go, but they were all based on milk whey. Online shopping revealed a few vegan-friendly cultures, but none that would arrive before I needed them (I had not left myself enough time to order the ingredients online and prepare them). Out of curiosity, I checked the packets of probiotic capsules down at the pharmacy and found that they did indeed contain the bacteria needed to turn milk into yogurt. Success! But I needed only a single capsule, and they were sold by the jar. Partial success then; I had a solution but it was a wasteful one.

I had enough time to experiment before I'd need to get some probiotics, and bought two tubs of the least flavoured soy yogurt I could find. When using unsweetend yogurt as a culture, a couple of tablespoons is enough to get the next batch going. Omitted from advertising on sweetened yogurt packaging is that they've been pretty much sterilised before sale and contain barely enough live bacteria to be called yogurt. So using a sweetened yogurt as a starter culture, I used six times as much as I usually would, a full 180ml tub.

I started two batches of yogurt—using my improvised yogurt makers—so that I could try two types of soy milk at once. The milks used were: Macro-Organics (Woolworths homebrand with a pretty label) and Vitasoy. After ten or so hours, I unscrewed the lids of the makers, took out the canisters of yogurt and tried them. The Vitasoy yogurt was still sweet, entirely liquid and had only the most vague taste of yogurt. The Macro-Organics yogurt was similar, but had an added foul aftertaste. At this point, I'd usually transfer the yogurt to the fridge and eat it the next day. Instead I refilled the maker with hot water and returned the Vitasoy yogurt to it for another ten hours. The Macro-Organics was abandoned as a failed experiment.

It took two days for me to ferment the Vitasoy milk to the point where it could be called yogurt. It was still runny and sweeter than I cared for, but that was all I was expecting. Vegan yogurt is runnier than dairy, thanks to the makeup of the milks that can be used, and is typically thickened using agar-agar to give it the desired texture.

So, it is possible to use commercial soy yogurts as a culture to produce a vegan substitue for greek yogurt, but only if you've got a few days of experimentation time to spare.