Water to extract ratio

I was at my LHBS talking about how I could have possibly scorched the wort of my double IPA as badly as I did when they finally asked how many gallons of water I was boiling with. Well, only have a five gallon pot, I explained, so I went with a four gallon boil and then topped it off appropriately. It was at that moment that all three guys behind the counter (it was a slow day) reeled in head noddings and “oh man’s”. I have never heard of a requirement of water to extract before, but they made some compelling arguments about how the extracts wouldn’t fully dissolve and how that would effect hop utilization as well.

Thoughts? This is foreign territory for me, and I left a little early feeling embarrassed (though that wasn’t their intention) about my lack of knowledge.

The guys you spoke to were right. The density of the wort sugars in the boil will affect the hop utilization, the color of the final beer, and can possibly lead to scorching if not fully desolved. All of these things can affect AG brewing as well (the last only if you add sugar and don’t stir enough), which is why you can’t just scale everything linearly if you change the OG of your recipe.

But there are some easy ways to get around this. First, mix the extract very well. Best to do this by bringing the water to a boil, removing it from the burner, and then adding in the extract. Stir until it is totally dissolved before putting the kettle back on the heat.

If light color is important, you can use the late extract method. For this, you add half the extract at the begining, and then only add the rest 15 minutes before the end of the boil. That gives it enough time to ensure you kill any microbes present, and allows the hot break to form.

Adjustment of hop bittering is more complicated. You’ll need to read up on that.

Was this a 5 gallon recipe or 10 gallon? I brew 5 gallon extract recipes. My boil begins with 2.5 gallons of water. Bring the water to a boil, turn off heat (electric stove), pour in LME and/or DME slowly while stirring constantly. Return to boil with high heat setting then turn heat down to maintain the boil. I will stir the wort about every 5 minutes. Never had any scorching. Takes about 2 large bottles of beer to do the boil. If you had scorching the most likely cause was insufficient mixing of the fermentables, perhaps combined with to much heat. A 4 gallon wort in a 5 gallon pot. That would be living to close to the edge of a boil over for me.

It was a five gallon recipe, and I use fermcap and it works like a charm. Avoids boil-overs like magic. I stirred the LME very thoroughly, but given the amount of extract it just wouldn’t dissolve properly (I’ve since figured out) so the scorching was inevitable.

Any recommended sources on adjusting bitterness?

Does anyone have any sources on the actual ratios or where I can read up on isomerization effects with sugar density?