Homebrew Flaws (Part 3) By: Tom Ayers
This week I’m going to continue my discussion of common homebrew flaws. Last week I discussed Diacetyl, DMS, and Estery. This week I’ll touch on Grassy, Light Struck, and Metallic. I’ll cover general recognition, causes, fixes, and preventative measures for each.
The smell of fresh cut grass is a wonderful reminder of the spring time, while leaves are a gentle reminder that fall is approaching. In life they can both be good, in beer they generally are not. This flaw is obviously recognized by the smell and taste of fresh cut grass or leaves. There are two general causes of of grassiness in a beer. The first is hops. If you dry hop your beer for two long you will get a solid example of this flaw. It is acceptable in IPA’s particularly DIPA’s but it should be kept to a minimum. Double IPA’s require massive amount of hops to obtain the big hop flavor and aroma necessary but monitor closely and sample regularly so you take the beer off the dry hops before this flaw sets in.
Beyond hops this flaw can come from old or poorly stored ingredients. Mostly because a musty aroma and/or flavor sets it. To prevent this make sure your store your grain in a cool, dark place. Do not let them get damp and if you can store them air tight do so. Don’t crush the grains until you absolutely need to if at all possible. Try to use crushed grains immediately, but do not go longer than a couple of weeks if you need to order crushed grains ahead. Side note: A grain mill will pay for itself in no time by allowing you to buy in bulk and crush as needed. If you’ve already run into this problem let the beer age some and it may fade, particularly if it comes from hops. If it is from older ingredients it may linger. But letting it sit won’t hurt.
Trust me, you’ve probably experienced this flaw. Pop open a light lager in a green bottle and you will get hit in the face with it. If you are unsure take a beer in a green bottle and stick it on your window seal in the sun for three days. When you open it your neighbors will experience this flaw! It will smell like a skunk. It is as simple as that. And it will jump out of the bottle. This aroma is caused by the reaction of hops in the beer with sunlight or fluorescent light. If you have it in your beer try aging it and keeping it out of light as it may fade, however you probably won’t be able to get rid of it. To prevent it use only brown (or ceramic) bottles. Green and clear bottles do not block the necessary light wavelengths to prevent this from happening. Brown bottles are much better at doing this. Do yourself a favor and save the clear/green bottles for cider or wine. You can certainly use them if you are disciplined about keeping them out of light, but it is just easier to use brown bottles. Lastly, store your beer in a dark place. An unlit fridge is nice as it slows aging and prevents light exposure, but a closed box will work too.
I personally haven’t experienced this flaw very often in a home brewed beer (my own or during judging). This flavor comes across as a coppery like or tin like flavor. Think about sucking on a penny and you have a decent idea. It can be caused by the beer coming in contact with unprotected metals. Aluminum and stainless steel pots are fine, however if you use a ceramic coated pot, be sure it isn’t chipped to the underlying steel. This absolutely will contribute this flavor. If your water is high in iron this will also be a problem, you will need to carbon filter or use an alternative water like RO or distilled water.
Unfortunately you cannot really fix this flaw. You could try to cover it up by blending it with another beer or adding an additive flavor like vanilla bean, coffee, or fruit. All of these seem like a lot of work to fix a bad beer. However, this is probably a minor flaw in your beer so I suggest drinking it. If it is overwhelming just get rid of it. Life is too short to drink bad beer.
Next week I’ll continue discussing more flaws and their prevention/correction.
As always, if you’d like more homebrew information, follow me on twitter @Tom_Ayers. If you have any questions, comments, or topic requests send me an email at AyersBrewing@gmail.com and I’ll be sure to respond. Cheers and happy brewing!