Short answer: merino is the everyday workhorse, cashmere is the softest and the most delicate, and alpaca sits between them, a smooth, dense fibre that suits a vest you want to wear hard. Our Alpaca Rittervest blends alpaca and merino, 34% alpaca, 33% merino and 33% nylon, $349.

I own Ritter, and people ask me which fibre they should pick before they ask me about the vest. Here is how I would think about it, whoever you buy from. I do not make a cashmere vest, so I have no reason to talk it down.

Merino: the one that does everything

Merino is fine, easy to knit and easy to care for, which is why it shows up in everything from base layers to suit jackets. It is a sensible default if you want one layer for most days. Its weakness is that on its own it can pill and lose shape at the elbows and hem with hard wear.

Cashmere: soft, and treat it gently

Cashmere comes from goats and is prized for how soft it feels against the skin. It is also fine and delicate, so it asks for careful washing and does not love a bag strap or a seatbelt. It is a lovely sweater fibre. For a vest that goes to the office, the airport and the sidelines, I would not choose it for toughness.

Alpaca: smooth, dense and long-wearing

Alpaca fibre has a smooth, slippery feel and drapes well. It comes from alpacas raised in the Andes, and it is a warm fibre, so it suits cold mornings and cool evenings better than a hot day. Many people who find some wool scratchy are comfortable in alpaca, although skin is personal and I cannot promise it for everyone.

Which vest for which day

• Office and client dinners: a plain knit that sits flat under a blazer. I wrote up what works under a blazer.
• Travel: a knit that comes out of a bag looking the way it went in. See the one-bag travel layer.
• Weekends and golf: something you can toss in a car without worrying about it. Blends do this better than a single delicate fibre.
• Gifts: a colour that goes with everything and a size that has easy exchanges. See gifts for the dad who wears vests.

Why we blend

The Alpaca Rittervest is a felted knit that mixes alpaca for the feel, merino for structure and nylon for durability, made in small batches in Peru. It has a plain full-zip front, two hidden zip pockets at the hip and no logo. It comes in eight colours in sizes S to XXXL. Shipping is free in the US, and returns and size exchanges are free for 30 days.

Questions I get asked

Is alpaca warmer than wool? It is a warm fibre, but how warm a garment feels depends on the knit, the weight and what you wear under it, so I will not give you a number. For a vest, the fibre matters less than the fit.

Is alpaca softer than merino? Many people find it smoother. Cashmere is generally the softest of the three.

Is a blend worse than a single fibre? Not for a vest you wear often. A blend can wear better than a single delicate fibre, which is why we use one.

Can I see it first? Order it, and if it is not right, returns are free for 30 days.

If you want the one I make, the Alpaca Rittervest is the plain one, and I answer the emails myself.