Raw almond butter

Update: Please also see my other almond butter posts:

• Homemade almond butter (using roasted almonds)
• Can you freeze almond butter?

Ack. This is going to look like I just can't let go, but the fine folks from Hangry Pants (love that name, BTW) asked about processing raw almonds instead of roasted ones, so I figured it'd be much better to find out for sure if there are really any differences than to spout off some half-cocked nonsense.

Guess what. They're different.

In short, without adding extra oil to the ground almonds, it takes about twice as long for a food processor to turn raw almonds into a creamy paste/butter as it does for roasted almonds. In my specific case, the right consistency was reached at 13 minutes.

Why is this? It's possible that the roasting heat weakens the almonds' cell walls so that oil is released faster, but I'm only speculating and don't really know the answer. That being the case, I won't bore you with another 286,973-word dissertation and just let the pictures do most of the talking here. The total elapsed processing time, in 30-second intervals, is superimposed on the food processor's spindle:

A couple of other notes and observations:

• You can see my original almond butter recipe, using roasted almonds, here.
• The almonds did not turn into random shades of brown during processing. As the 00:30 and 01:00 photos show, most of the lighting for this setup came from the side (bottom left in the images) instead of the top. The specific shade in each photo only indicates how thickly the almond particles coated the sides of the workbowl (thus blocking the light) and does not reflect color changes in the ground almonds themselves.
• Overall, though, roasted almonds do make for a darker finished product than raw almonds, which should be expected. This is a color sampling from my two batches:
  
• Unlike making almond butter with roasted almonds, I had to scrape down the sides of the workbowl this time. To preserve the grinding and clumping characteristics, this was only done after each photo was taken.
• A side benefit of the extended processing time is that it really isn't crucial to stop the machine at some exact specified moment. Although I said the right consistency was reached at 13 minutes, the changes in texture from about 11 minutes onward were really pretty minor.
• I have no idea if the specific equipment matters or not, but I used a full-sized KitchenAid food processor to make both this and the roasted almond butter.
• I split this batch and froze part of it. The result after thawing? Skin, stir, and a side-by-side tasting: no difference. So, homemade almond butter can be frozen with no problems.
• Update 2009-09-11: Based on a question in the comments below—homemade almond butter should be refrigerated, and you should keep it there for no more than four months. This is to prevent (or delay) the oil from going rancid. If you need longer storage, freeze it.

A NOTE FOR RAW FOODISTS

The almonds started at room temperature and became warm as a result of the long processing time. I did not take any measurements, but the temperature increase may be a concern for strict raw foodists. I don't know what effects starting with frozen almonds would have.

Update 2009-09-06: By law, since September 2007 all almonds grown and sold in the United States must be pasteurized, either through fumigation or heat treatment (PDF). This means that domestically-grown almonds are no longer acceptable for people on a strict raw-foods diet, even though marketers can still label these almonds as "raw" for sale to consumers. This law does not apply to foreign-grown almonds imported into the US, however, so if you're on a raw regimen, it would be advisable to assume that regular supermarket almonds are not raw (no matter what the label says) and buy truly raw almonds only from a specialist supplier.