"They're both microbiological wonders," James Morton says of two of his great loves: sourdough and beer brewing. "They're both very scientific, very measured. And they're both ways of achieving taste nirvana."

And they're the subject of his two new cookery guides, From Scratch: Sourdough and From Scratch: Brew.

The former Great British Bake Off contestant, who lives in Glasgow, has been making sourdough since his late-teens, and has been pleased to see the lockdown-friendly bread in particular get "the recognition it deserves". His other bread books actually sold out as a result of the pandemic rush - but as a doctor, there have been lows during this past year, as well as the bread-based highs.

"We've all had a few crises, a few wobbles," says Morton, who also become a father during the pandemic, to daughter Lily. But, he adds, "I've got a feeling we're getting there. I'm feeling really, really positive."

So why do you think sourdough became so popular during lockdown?

"It's a labour of love, there's this story of creating something from literally just flour and water, bringing it to life, sharing it with other people, sharing it online - which has become a really important part of it. And the fact it's just awesome. You can make bread as good as the best bread in the world, in the comfort of your own home."

Is there a secret to producing perfect sourdough?

"Sourdough is just a mixture of flour, water and salt, but there's all this biochemical madness going on in order for you to get this loaf of bread, and the most important part of that is the starter. It's just flour and water that you leave to go off, it starts to bubble, it's full of yeast and bacteria, and if you neglect it, let it just fizzle out and fade over time without feeding it, or taking proper care of it, it will just not produce good bread."

What mistakes do people always make?

"People say, 'My loaf has just fallen apart into this wet pancake'. But almost always, even if you think your problem is completely unrelated, it's down to the starter; your starter isn't active enough. You just need to feed it more and feed it better."

Do you name your starter?

"Absolutely not. If the starter's not going well, or it's really, really faded, you should just get rid of it; you shouldn't have any sentimental attachment. There are people who have starters that are hundreds of years old and like to boast about this. But that doesn't actually make any better bread.

"Starter hotels even exist. People will drop off their starters to other people to look after when they're on holiday. You don't need to do that. Just stick it in the fridge, it'll be pretty resilient, and then give it a couple of feeds when you get back."

Feeding it sounds quite complicated...

"If you try and feed it every day, you're just going to forget; you're setting yourself up for failure. The key is actually to keep it dormant in the fridge and only when you need it, take it out. Feed it with far more flour and water than is in the starter, and you're gonna have a good loaf. Your starter should always at least double in size before you use it. And if you stick to that, you will not go far wrong."

How often do you bake bread?

"I make bread two to three times a week, two to three loaves at a time. So we get through a lot of bread. I've been making the focaccia and my staple, the country loaf [in the book]. It's mostly white, with a bit of rye or oatmeal in there to give it some earthy crunch."

What's your go-to toast topping?

"Peanut butter and banana on toast - I think it's my number one at the minute. Peanut butter and jam - mostly involving peanut butter, to be honest, or scrambled eggs on toast. Anything that involves breads, I am pretty much for."

When did you initially find yourself drawn to brewing beer?

"I did get into it as a student. One of my friends happens to be a UK champion homebrewer, and so he introduced me to this idea that homebrew wasn't just something that tasted dodgy, brewed in these big plastic buckets with little airlocks, that bubbled on top and was always sour, or the bottles were exploding."

Why is it worth the effort of brewing your own?

"My first homebrew pint, I opened up, it fizzed everywhere and tasted sour, infected with the wrong sort of bugs - probably that had got there from my sourdough starter, actually. But the first taste of my first proper homebrew - which was an oatmeal stout in a 500ml Samuel Smiths bottle, with the remnants of gold foil around the top - I popped the cap and there's this amazing hiss, and that hiss and that first bottle, there is no feeling like that in the entire world, it is awesome. Then you pour it and it's black with a head that almost looks like a pint of very nice Guinness. And you taste it, and it's just so much better than any Guinness you have ever had."

How straightforward is brewing?

"Like a sourdough, you've got to follow these scientific steps to get really, really good results, but once you've got the hang of it, it is possible."

What should every budding brewer keep in mind?

"Everything needs to be super, super clean, and not just clean but sanitary. What I mean by that is, it's covered in some food-safe disinfectant of some kind to stop the beer getting infected, which is what happened to my first ever batch. If it becomes infected, it could become sour, smelly, sulphurous or over carbonated and the bottles could explode. So it's very, very important not to let it become infected. The only thing you want in your beer is your yeast, which causes the fermentation which creates your alcohol and your carbon-dioxide that makes it fizzy."

Has the pandemic affected your eating habits?

"Not really, to be honest. We get our veg box and try to try to keep everything as local and as seasonal as possible, which in Scotland means lots and lots of potatoes, carrots and swedes at this time of year! We're getting into some spring greens and some cabbage, I hope."

What about trying out meal kits?

"We've done absolutely tons of them, which has been great, having a baby. Having a load of really good restaurants very nearby means there's loads of dine-at-home options and we've not had to get a babysitter, so we're just able to have date nights and the baby's been upstairs asleep."

Do you still watch Bake Off?

"I watch it most years. I watched this year. It was a really nice light relief from [the pandemic]. They'll be filming the new season soon."

Does it bring back memories?

"Yes, it's not always good! It makes me feel stressed, like I'm going to be judged again!"

From Scratch: Sourdough and From Scratch: Brew by James Morton are published by Quadrille, priced £12 each. Photography by Andy Sewell.