Technical Field The present invention relates to a low alcohol or alcohol free fermented malt based beverage, such as beer having a flavour profile very close to regular lager beer. The present invention also concerns a method for producing such malt based beverage.

Background for the invention Low alcohol or alcohol free beers have different definitions depending on the national legislation of the different States. In the context of the present invention, a "low alcohol beer" is defined as a beer having an alcohol content of not more than 0.7 vol. %, and an "alcohol free beer" as a beer having an alcohol content of not more than 0.1 vol.%. The present invention concerns both types of beers, jointly referred to in the following as "NA beers", and including beers with even lower alcohol contents of not more than 0.05 vol.%. Attempts to produce NA beers having a flavour profile close to regular lager beers have had limited success in the past. The present invention also relates to fermented malt based beverages having an alcohol content of not more than 0,7 vol.%, preferably not more than 0,05 vol.%, and even more preferably not more than 0,05 vol.%.

One way of producing NA beer or fermented malt based beverages is to carry out normal fermentation of the wort and to remove the alcohol by distillation, evaporation, dialysis, or reverse osmosis techniques. These techniques involve high capital or energy costs, and have limited production rates. Alternatively, so called cold contact fermentation, as described e.g., in US6689401 and US5346706, allows to reduce the fermentation rate of sugars in contact with yeast, whilst by-products provided by the yeast are still present as in alcoholic lager beers, giving a distinct aroma thereto. NA beers produced by cold contact brewing, however, generally show an excess sweetness due to the presence of considerable amounts of unfermented sweet sugars.

In some cases, the alcohol content of a beer needs be reduced by diluting it with water, with the obvious detrimental consequences on taste if too much water is needed to attain the target alcohol content (cf. e.g., US4970082).

It is well known that a number of enzymes, in particular cx-amylase and β-amylase, formed during germination of malt are responsible for the production of fermentable and non- fermentable sugars from starch in a mash. Starch is a large and complex carbohydrate molecule consisting of a large number of glucose units joined together by glycosidic bonds (= polysaccharide), β-amylase breaks down these units from the end molecules producing more low-order sugars like maltose, which are easily fermentable by yeast, and thus yielding more alcohol. <x-amylase, on the other hand, breaks down starch from the inside, and starts cutting off links of glucose creating more higher-order sugars and dextrins, such as maltotetraose, maltopentaose, maltohexaose, and maltoheptaose, which are less fermentable by the yeast, and thus yielding less alcohol.

GB21 81 50 proposes a method for producing a wort of low fermentatbility, by inactivating β-amylase in a malt and reacting a-amylase with starch within the malt to produce a wort rich in unfermentable sugars, β-amylase is inactivated thermally at temperatures of up to 85°C, and thermostable α-amylase is added to the mash to yield a wort of fermentability of 30 to 50% instead of 70% as would be typical in a normal mash. The "fermentability" expressed in percent is the weight proportion of the wort which will react with yeast to produce alcohol. A beer with low residual sweetness having an alcohol content of 1 .55 vol.% compared with 3.3 vol.% for the control batch was produced from such low fermentability wort. By addition of lactose in the copper, the alcohol content was further reduced to 1 .2 vol.%.

It can be seen from the above review that it still remains a need in the art for a NA beer having a flavour profile close to normal lager beer, and which production is cost effective.

Summary of the invention

The present invention is defined in the appended independent claims. Preferred embodiments are defined in the dependent claims. In particular, the present invention concerns an alcohol free or low alcohol fermented malt based beverage such as beer having an alcohol content of not more than 0.7 vol.%, characterized by a relationship

y > A x ^b

Wherein A = 0.25 , preferably 0.3, more preferably 0.35, most preferably 0.45, and b = 1 .5, preferably 1 .0, and wherein,

· x is the ratio between unfermentable over real extracts, wherein the unfermentable extract is the value of the real extract less the total content of sweet sugars, which consist of fructose, maltose, glucose, maltotriose, and saccharose, and

• y is the ratio between the combined content of maltopentaose, maltohexaose, and maltoheptaose over the total amount of main sugars, wherein the main sugars consist of fructose, maltose, glucose, saccharose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose. In a preferred embodiment the alcohol content of the malt based beverage according to the present invention is not more than 0.5 vol.%, preferably not more than 0.3 vol.%, more preferably not more than 0.1 vol.%, most preferably, not more than 0.05 vol.%. In terms of absolute values, it is preferred that the unfermentable extract is at least 4.0 g / 1 00 ml, preferably at least 5.5 g / 1 00 ml, more preferably 6.0 g / 1 00 ml, most preferably at least 6.5 g / 1 00 ml, and the real extract is at least 5.0 g / 1 00 ml, preferably at least 6.0 g/ 1 00 ml, more preferably at least 7 g/ 1 00 ml. A malt based beverage according to the present invention should preferably not have a total content of sweet sugars higher than 3 g / 1 00 ml, preferably not higher than 2 g / 1 00 ml, more preferably not higher than 1 .5 g / 1 00 ml.

The present invention also concerns a method for producing a malt based beverage, such as NA beer comprising the following steps:

(a) Mashing grain grits by inactivating β-amylase and reacting a-amylase with starch within the grits to produce a wort of fermentability of not more than 29%, preferably not more than 25%, more preferably nor more than 20%; and

(b) Fermenting the thus produced wort by a cold contact process to produce a malt based beverage having an alcohol content of not more than 0.7 vol.%, preferably not more than 0.5 vol.%, more preferably not more than 0.3 vol.%, most preferably not more than 0.03 vol.%.

The grain grits should comprises malt, preferably admixed with corn grits and/or rice grits. In particular, the grits may be composed of 30 to 1 00 wt% malt and 70 to 0 wt% corn grits. The β-amylase is preferably inactivated by bringing the temperature of the grits mash over 75°C, preferably over 85°C and wherein thermostable a-amylase is added. For example, the mashing may comprise the following steps: (a) If any, adding to a corn grits mash an appropriate amount of thermostable oc- amylase and heating the corn mash to a temperature of 85 to 1 00°C;

(b) Mashing in malt at a temperature of 70 to 1 00 ³ C, preferably 78 to 85°C, and combining it with the corn mash, if any, and bringing the temperature of the thus obtained mash to higher than 75°C, preferably higher than 85°C and adding thereto thermostable a-amylase;

(c) Raising the temperature to a value of 90 to 98°C and transferring the mash to lautering.

The wort is then boiled and has then a gravity comprised between 6 and 20°P, preferably between 8 and 1 2°P, more preferably between 9 and 1 ΓΡ. The wort is thereafter cooled to a preferred temperature of 2 to 8°C, preferably of 2 to 5°C, and then cooled to 2 to 0°C for the cold contact fermentation stage. The method of the present invention is suitable for producing a malt based beverage as discussed above.

Brief description of the Figures

For a fuller understand ing of the nature of the present invention , reference is made to the following detai led description taken in conjunction with the accompanying drawings in which :

Fig ure 1 : shows a schematic representation of the main steps for the production of a fermented malt based beveage.

Fig ure 2 : shows an embodiment of temperature-time profile in the cereal cooker and the mash tu n, according to the present invention.

Fig ure 3 : shows a plot of the ratio of x vs y for a number of beers according to the present invention compared with prior art commercial NA beers and showing the function, y = A x ^b , defining the subject matter of the present invention. Detailed description of the invention

The fermented malt based beverage of the present invention has an alcohol content of not more than 0.7 vol.%, and may even have alcohol contents of not more than 0.1 vol.% or even 0.05 vol.% with a flavour profile which preferably remains very close to normal lager beer. The flavour profile of a beer is a very complex issue and is usually assessed by a panel of experts marking several dozens of parameters such as sweetness, fruitiness, bitterness, after-bitterness, caramel note, worty note, and the like. Although some flavour characteristics may be asoociated with a specific component, such as bitterness being associated with the presence of hops, the overall flavour profile is beyond a full understanding, as there are a myriad of parameters controlling it: types and contents of the components used, time-temperature profiles, pH, etc. Any change in one of said parameters, affects the flavour profile of a beer.

A typical brewing process involves the main steps schematically depicted in Figure 1 . Malt (21 ) is mashed in a mash tun (1 ) to transform starch into sugars. It is possible to add thereto grain grits (22) previously cooked in a cereal cooker (2). When mashing is over, mixture is transferred to lautering where the solid phase is separated from the liquid wort (23), the latter being loaded in a copper (3), sometimes also called kettle. The wort is boiled and hops is added, giving to beer its distinct bitter taste. During this stage, many reactions, such as Maillard reactions, occur, developing various flavours and aroma characteristic of each beer. At the end of the boil, the hopped wort is clarified and cooled down prior to transferring it into a fermentation tank (4) where the fermentable sugars, in presence of yeast (25), will be transformed into alcohol and CO2. After fermentation is completed, the liquid is conditioned for several days or even weeks in conditioning tanks (5) until the beer has matured and is ready to be bottled or transferred into kegs (6). The malt based beverage of the present invention can be produced by a method as disclosed supra, further characterized in that it comprises:

(a) Preparing a wort (23) of fermentability not higher than 29%, preferably not higher than 25%, more preferably at most 20%; and

(b) Fermenting the thus prepared wort in a fermentation tank (4) by a cold contact process.

Such low fermentability wort (23) is prepared in a mash tun (1 ) by inactivating β-amylase in a grain grits mash and reacting α-amylase with starch within the grits, β-amylase is best inactivated by heating the mash at a temperature higher than 75°C, preferably higher than 85°C. Because a substantial fraction of α-amylase formed by malt may be inactivated too at a temperature higher than 75°C, it may be necessary to add thermostable α-amylase to the mash, for instance Thermamyl of Novo Enzyme. The mash is maintained at such thermal conditions until a wort (23) of fermentability of at most 29%, preferably at most 25%, more preferably not higher than 20% is obtained, resulting in a wort which is rich in poorly fermentable dextrins, typically maltopentaose, maltohexaose, and maltoheptaose, and concomitantly which is poor in highly fermentable sweet sugars (i.e., glucose, fructose, maltose, saccharose, and maltotriose). These worts are richer in dextrins and poorer in sweet sugars than a wort of say 30% fermentability as disclosed in GB21 81 50. Beyond yielding a beer with less alcohol after the fermentation process, it is believed that the higher content in dextrins is responsible for less Maillard reactions during the boiling step in the copper (3). The Maillard reaction is

"a chemical reaction between an amino acid and a reducing sugar, usually requiring heat, [wherein] the reactive carbonyl group of the sugar reacts with the nucleophilic amino group of the amino acid, and forms a complex mixture of poorly characterized molecules responsible for a range of odors and flavor[u]rs [...]. In the process, hundreds of different flavor[u]r compounds are created. These compounds in turn break down to form yet more new flavor[u]r compounds, and so on. Each type of food has a very distinctive set of flavor[u]r compounds that are formed during the Maillard reaction" (cf. http: / /en.wikipedia.org /wiki / Maillard_reaction). Reducing Maillard reactions in the beer brewing process is not an objective per se, but it was observed that in the case of NA beers, it yields a flavour profile which is closer to normal lager beer. Without being bound by any theory, it is believed that a higher fraction of dextrin with respect to sweet sugars in the mash reduces the number of reactive carbonyl groups available for Maillard reactions during the boiling of the wort in the copper (3).

Preferably the grain grits comprises malt (21 ), such as malted barley, which is preferably admixed with corn grits and/or rice grits (22). For example, the grits may comprise 30 to 1 00 wt% malt and 70 to 0 wt% corn grits and/or rice grits. The water to grist ratio in the mash is preferably comprised between 3 and 6, ptreferably between 4 and 5, mote preferably between 4 and 4.5, and the pH is mainatinaed between 5 and 7, preferably between 5.2 and 6, more preferably between 5.4 and 5.6. Figure 2 shows an example of temperature-time profile during mashing. In the embodiment illustrated therein, malt (21 ) is admixed with grain grits (22), for example corn grits, which is first cooked in a cereal cooker (2) at a temperature between 85 and 1 00°C. Thermostable a-amylase can be added to the cooking corn grits. Malt (21 ), e.g., barley malt, is mashed in a mash tun (1 ) at a temperature of 78 to 85°C with additional thermostable a-amylase. The corn grits is added into the mash tun containing the malt and the temperature is raised to above 85°C. The necessary amount of thermostable a-amylase may be added at any time during mashing. When mashing is completed, the temperature is raised again to 90-98°C for the transfer to lautering to recover a wort of fermentability of at most 25%, preferably, at most 20%.

After boiling of the wort in the copper in presence of hops, the boiled wort preferably has a gravity comprised between 6 and 20°P, preferably between 8 and 1 2°P, more preferably between 9 and 1 Ρ. The wort is then cooled to a temperature of 2 to 8°C, preferably of 2 to 5°C, before transferring it into a fermentation tank (4), wherein the wort is fermented by a cold contact process at a temperature of 0 to 2°C for 1 2 to 72. It is possible to flush beer or malt based beverage shortly with CO2 before transferring it to conditioning tanks to yield a NA beer or malt based beverage of alcohol content of not more than 0.7 vol.%, down to even not more than 0.05 vol.%. Some dilution is not excluded but only to fine tune the final alcohol content of the beer, and not as the main mean to reach a low alcohol content. Optionally sweet sugars or other additives can be added to the fermented malt based beverage in order to alter the flavor profile so as to obtain sweet beverages wherein the beer flavor is substantially masked.

Different batches of beer obtained by such process, all having an alcohol content of less than 0.45 vol.%, were tested by a panel of experts, and their conclusion was that their flavour profiles were particularly close to the ones of STELLA ARTOIS and JUPILER BLUE, two popular lager beers in Belgium. Table 1 lists the alcohol contents, extracts and sugars contents of a number of commercial NA beers (CEXl to CEXl 6) compared with the ones of NA beers according to the present invention (EX1 to EX1 3). As many of the NA beers of the comparative examples belong to the competition, it is not always known how they were processed. It is known, however, that the NA beer of CEX3 was obtained by arresting fermentation by a cold contact process, whilst the NA beers of CEXl 4-1 6 were obtained by evaporation. It can be seen from Table 1 , that the sweet sugars contents (= fructose, glucose, maltose, saccharose, and maltotriose) of the NA beers according to the present invention are quite low when compared with CEX3 obtained by a cold contact fermentation process. This is to be expected, since in these beers, the wort contains a high proportion of fermentable, sweet sugars, which are not allowed to ferment by the cold contact process, and thus remain in the beers, giving a strongly sweet taste. Based on their high contents of sweet sugars, it can be assumed -with no guarantee- that the NA beers of CEX4 and 9 were also fermented by cold contact. On the other hand, as could be expected, the content in sweet sugars of NA beers of CEXl 4-1 6 is very low, since the sweet sugars present in the wort were allowed to ferment, but the alcohol thus produced was withdrawn by evaporation. Based on their low amounts of sweet sugars, it can be assumed that the NA beers of CEX1 0&1 1 were obtained by retrieving the alcohol after fermentation, by any process such as evaporation, distillation, etc.

All the NA beers on the market have an unfermentable extract below 5.0 g / 1 00 ml, which is lower than the one of the NA beers of the present invention. The unfermentable extract is defined as the value of the real extract less the total content of sweet sugars, which consist of fructose, maltose, glucose, maltotriose, and saccharose. Another observation is that the content of high molecular weight dextrin, viz., maltopentaose, maltohexaose, and maltopentahose is quite low in the NA beers on the market, compared with the NA beers according to the present invention; the combination of maltopentaose, maltohexaose, and maltopentahose is hereinafter referred to as "malto-penta/hexa/hepta-ose". Figure 3 plots the ratio of unfermentable to real extracts, hereinafter referred to as "x", vs the ratio of the contents of malto-penta/hexa/hepta-ose to total sugars, hereinafter referred to as "y". The total sugars consist of fructose, glucose, maltose, saccharose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltopentahose. Relative values bounded between 0 and 1 were considered to account for possible dilutions of varying degrees between NA beers of different origins and obtained from different processes in the hope of yielding a relationship between these two parameters and thus of defining a master curve for NA beers. Indeed, it was observed that all the NA beers on the market (white circles) clearly followed a master curve of the type, y = A x ^b regardless of their origins (cf. thin dotted line in Figure 3), whilst the NA beers according to the present invention (black circles) distinguished themselves clearly from this trend.

The fermented malt based beverages of the present invention therefore characterize themselves from the beers on the market in that

wherein A = 0.25 and b = 1 .5 , as represented in Figure 3 with a thick solid line. In a preferred embodiment, b = 1 , to yield a linear relationship represented in Figure 1 with a thin dashed line. A may take any value between 0.25 and 0.45, such as 0.3 or 0.35, and the power b may take any value between 1 and 1 .5 , such as 1 .25 or 1 .35. In a preferred embodiment, the fermented malt based beverage of the present invention is characterized by:

• a ratio x between unfermentable over real extracts of at least 25%, and/or

• a sugars ratio y of at least 25%, preferably at least 30%, more preferably at least 35%

As discussed above, the preparation of a wort of fermentability not higher than 25% combined with a cold contact fermentation process allows a fermented malt based beverage and in particular NA beer to be produced having a flavour profile very close to normal lager beers and an alcohol content lower than 0.7 vol.%, such as not more than 0.5 vol.%, preferably not more than 0.3 vol.%, more preferably not more than 0.1 vol.%, and even not more than 0.05 vol.%. It is believed that such a close matching flavour profile of the NA beers of the present invention with normal lager beer is due inter alia to a high value of real extracts yielding body, in combination with a high amount of unfermentable extracts, and in particular of a high extract of unfermentable malto-penta/hexa/hepta-ose, resulting in a low amount of sweet sugars. In particular, a malt based beverage according to the present invention may have a real extract of at least 5.0 g / 1 00 ml, preferably at least 6.0 g/ 1 00 ml, more preferably at least 7 g / 1 00 ml and an unfermentable extract of at least 4.0 g / 1 00 ml, preferably at least 5.5 g / 1 00 ml, more preferably 6.0 g / 1 00 ml, most preferably at least 6.5 g / 1 00 ml. This should result in a total content of sweet sugars not exceeding 3 g / 1 00 ml, preferably not more than 2 g / 1 00 ml, more preferably not more than 1 .5 g / 1 00 ml.