How much peated malt to get a hint of smoke?

As a Scotsman and a professional brewer the answer to how much peated malt to put in a Scotch Ale is zero.

The smoked malt beers I first came across were German never Scottish.

In Scottish breweries we used to pay special attention to testing for any peated malt contamination of our malt deliveries because so much peated malt could accidently come into contact with brewers malt.

If you want to make smoked malt beer go ahead but take it from me it is not Scotch Ale or even Scottish Ale.

Happy brewing!

George

I actually began to write up an answer to this question back when it was first asked, but I scrapped it because I didn't want to sound like an idiot. Now that I can confirm what happened, I feel more comfortable answering.

I pulled Stone's Smoked Porter recipe from their book, and brewed it a couple of months back. It calls for ~3-4% peated malt. Me being uneducated in the ways of peated malt biffed it and wound up with 4-5% peated malt in my brew. I went to keg it, and I was sorely disappointed. I didn't think I used enough. Then I started to hear everyone say that you want less than what I put in, and I was confuddled. I didn't know what I did wrong. Did I undershoot the percentage by accident when mashing in? I barely tasted any smokiness what-so-ever. I didn't hesitate to bottle off what was remaining in the keg a couple of weeks ago to make room in the keg for my next beer. Just now, I have the last remaining bottle (and the only bottle I've drank this from, the rest were readily given away to co-workers and friends) poured in front of me, and when I went to drink it, as mdma put it "Who put out a bonfire in my beer!?!"

Moral of the less than helpful but hopefully insightful in a different way answer, aging will have a profound impact on the flavor of peated malt. My beer wasn't matured by the time I took it out of secondary and kegged it (I don't have the records, but it likely sat in secondary for about a month and kegs for about 3 weeks after that before it went into bottles). After it sat still in bottles for a couple of weeks and the "green" flavors dropped out, it tastes entirely different. Hope this helps.

Purism aside about whether peated malt belongs in an Ale, I used peated malt in a Scottish Ale - just 0.7% of the grist. While I can't say I noticed a specific smokiness, there was a lot more going on in the beer ingredients-wise, but it did lift the ale and add complexity. I was very happy with the result. So, I'd go for 1%.

Best to add too little and work upwards - you'll still have a drinkable beer, but not necessary so if you add too much!