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I've been doing a lot of reading on brewing in preparation for my second batch. The first mention of using specialty grains that I found suggested boiling them in the brew water for a full hour. I then went out and got a brew book and started reading, When they first mentioned using grains, they said to NEVER boil the grains, just steep them in boiled water for 15 to 30 minutes depending on what kind of beer you're making.

So I'm just wondering, should I boil the grains, or should I steep the grains in hot boiled water?

Also, what is the purpose of doing this, what characteristics do the grains pass on to the beer?

Thanks :)

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Do you have the source that said to boil the grains? I've never heard this... –  Chris Dargis Jul 21 at 14:22
    
I'll see if I can find it, I may have misread it but I'm still curious as to the benefits of steeping specialty grains. –  Tory Hill Jul 21 at 14:25
    
Using specialty grain increases the complexity of the wort. The resulting beer flavor will be much better than using extract alone. –  Chris Dargis Jul 21 at 14:27
    
Specialty grains provide color, body, taste, mouthfeel, aromatic properties... –  Chris Dargis Jul 21 at 14:43

3 Answers 3

up vote 2 down vote accepted

To expand from Chris Dargis's comments, specialty grains are called that because they contribute more flavor than they do fermentable sugars. In extract and partial mash brewing (what you're looking at doing), the fermentable sugars come mostly from your extract, where the specialty grains supplement the beer by contributing other characteristics such as flavor (e.g. sweet, caramel, honey, biscuit, roast, depends on what type of grain), mouthfeel and head retention. Opposite of using extract is brewing using the all-grain brewing technique, where the brewer uses "base grains" instead of extract to get his fermentable sugars, as well as specialty malts. Similar to partial mashing, all-grain brewing requires the brewer to soak the base grains and the specialty grains together before filtering out the grains and boiling the wort. In reality, partial mash isn't the best, most intuitive title for the technique, think of it like a mini-mash.

As Denny explained, you do not want to boil specialty grains when partial-mash brewing. Water has a fairly high pH to start out with, which influences the extraction of tannins from the grains at high temperature, resulting in an astringent/bitter flavor (different from hop bitterness). Tannin flavor is never desirable in beer. The reason decoction mashing (part of all-grain brewing) can boil grains without extracting tannins is because the wort that they are boiling has a much lower pH than what you'll have when partial mashing. The reason it is lower is because they are soaking both their specialty grains along with their base grains, which when mashing both together, the pH is much lower than if you only steeped your specialty grains alone. You'll want to maintain a steady temperature between 150°-160°F for the steeping grains (assuming they're all malted grains being used). Any higher, and you'll extract tannins, any less, and you won't get the optimal sugar extraction from the grains. I've also seen some really wonky looking beers where they boiled the grains and the entire carboy looks like one giant yeast/protein cake.

As a bit of an aside from your two questions, here's an interesting, informative video from Brewing TV where they brewed two batches of beer of the same style. One was brewed partial-mash, the other all-grain. It helps to clarify the differences, and show how they compare in the end with tasting notes.

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Thank you very much scott, that was exactly the kind of answer I was hoping for :) –  Tory Hill Jul 21 at 20:44

For a partial mash (malt extract plus specialty grains), do not boil the grains. Put them in a large mesh/muslin bag and steep them in your brewpot at 155f for 30-45 minutes before adding your hops or extract.

Boiling the grains would release harsh tannic flavors that you don't want.

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Specialty grains need to be soaked in water at an optimal temperature for alpha amylase activity - 150-160F. Typically, 30 minutes is enough time for full flavor and sugar extraction. However, with specialty grains only, you aren't looking to get many fermentable sugars from the grains - only wort color and flavor. If you steep them in water hotter than 160F, you won't get many fermentable sugars extracted from them.

I would recommend just steeping at the temperature mentioned above. You do need to avoid burning the grains with direct heat contact. Also, avoid squeezing or compressing them as this will extract unpleasant tannins.

Edit: Removed statement that boiling grains is not dangerous in a partial mash.

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Thanks for the answer, Just a comment on the sqeezing of the grains, the two books I got suggest using a spoon to press the bag against the side of the pot to get as much liquid out of them as possible, then rinsing them with freshly boiled water to make sure everything gets into the wort, does this sound like overkill or is it all pretty much up to personal preference. –  Tory Hill Jul 21 at 15:15
    
The reason that boiling grains works for decoction is becasue the pH is so low. If you're putting the grains into a large kettle of water, there won't be enough grain to buffer the pH and it will very likely remain high. That could lead to extraction of tannins from the grain. For that reason, I would avoid boiling the grain at all costs, unless you have a reason to do it and are certain that the pH is in the correct range. –  Denny Conn Jul 21 at 15:19
    
@DennyConn Sorry but are you saying you "would boiling the grain at all costs" or do you mean "would avoid boiling the grain at all costs"? –  Tory Hill Jul 21 at 15:48
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Sorry for the confusion...I would AVOID boiling the grains. The only time that would be a good idea was if you were doing a decoction mash, and the circumstances for that are very different. (original comment now corrected) –  Denny Conn Jul 21 at 16:17
    
Seconding Denny, absolutely do not boil the grains in a partial mash. –  Scott Jul 21 at 16:22

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